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                                  • As of August 2019, we officially canceled XAF's React-based SPA UI project. We have made the decision to focus our efforts on Blazor going forward. For more information, see XAF - Important Changes to the SPA UI Strategy: The Future is Blazor. SPA-related content was removed from this article.
                                    This article contains FAQ for the former Mobile UI. It is currently in maintenance mode, which means that we will fix only critical bugs and will not make any new features. The article is intended only for users who already started developing Mobile UI applications. We do not recommend that you start new projects with the Mobile UI.

                                    Q:  Do you provide videos and demo apps that I can use to test the new mobile UI?
                                    A:  A simplified mobile version of our MainDemo app is available here.
                                    See also a short overview Overview Video on our YouTube channel (2m 40s).
                                    The Getting Started Tutorial article provides step-by-step instructions on enabling the mobile UI for an existing XAF application starting with v16.2.

                                    Q: What device form factors are supported?
                                    A:  We intentionally disabled the Desktop emulator, because we decided to focus our team resources on improving mobile devices support in the first place - the primary reason for creating the Mobile UI in XAF. We have not finalized UI and UX optimizations for larger screens, which requires a lot of resources, and this is not something our team can afford until we provide the first class support for smaller screens. If you would like to target larger screens, creating an XAF ASP.NET WebForms application with the New Web UI will be a better option in many scenarios as it is stable and is optimized for both tablets and desktop browsers.

                                    Q: Can I add a Mobile project to the existing XAF solution?
                                    A:  Yes, in versions prior to v19.1, you can use the Solution Wizard as described at Add a Project to Existing XAF Solution.
                                    UPDATE: Note that the "Mobile Application Project" item is removed with v19.1. The option to create a brand new Mobile UI project is still available, but it will likely be removed from the wizard in the future - we do not recommend our users start new projects with it.

                                    SUPPORT & LIFE CYCLE
                                    Q: Can I use this feature in production or create new apps with it?
                                    A:  No, we do not recommend it as the feature was not out of preview. For more information, see the "1.5 PRE-RELEASE SOFTWARE" section of our EULA or

                                    Q:  What are alternative ways to build a mobile app if this is a matter of urgency?
                                    A:  If you cannot wait for when our new Web & Mobile/Blazor UI is ready for production use, you can consider building a mobile web site or store-ready native app from scratch using DevExtreme or other UI frameworks (learn more...). In certain scenarios, an XAF ASP.NET WebForms application with the New Web UI optimized for smartphones or tablets can be a simpler, but still acceptable solution for many scenarios in the interim period. For more information, see T756688.

                                    Q:   How long will you support the ASP.NET-based Web UI?
                                    A:   Our primary focus in 2020 will be on XAF’s Blazor UI but we will do what we can to address the needs of those reliant on our ASP.NET WebForms UI. For instance, in 2019 we already supported the following popular WebForms features: user-friendly URLs, ImmediatePostData and reference properties in ASPxGridView's Batch Editmode without custom code, Spreadsheet Editor.
                                    It is important to understand that our Web UI has a large user base and there are many people who are satisfied with the current feature set. As long as this platform meets our customers and their clients' expectations and it is not costly for us, we will maintain it.

                                    PURE TECHNICAL QUESTIONS
                                    Q: How is the mobile client app built?
                                    A: The mobile client is a single-page HTML5/JavaScript application (SPA) based on DevExtreme components that is ready to be compiled by Apache Cordova (PhoneGap) into a native package that can then be submitted to app stores. If you follow this route, PhoneGap also provides libraries to access a device's built-in functionality such as a camera, accelerometer and contact list.

                                    Q: How to integrate a custom PhoneGap plugin?
                                    A: We added the article to our online documentation containing examples of using some popular Cordova plugins: Custom Plugins in Mobile Applications.

                                    Q: What are the supported mobile and desktop web browsers?
                                    A: All modern desktop and the mobile web browsers on popular operating systems, which are currently supported by DevExtreme.
                                    Note: The simulator may not work correctly in the Internet Explorer browser. This is a known issue described in the documentation. For development, consider using another web browser.
                                    Q: How is the backend application service built?
                                    A: The new XAF mobile application project automatically created from the XAF Solution Wizard in Visual Studio contains three main classes:
                                    1.  YourSolutionNameMobileApplication (MobileApplication.cs) - this class derives from the new MobileApplication class similarly to WinApplication or WebApplication in appropriate platforms. An instance of YourSolutionNameMobileApplication is created for each request from the client application.
                                    2. DataService (DataService.svc) - this is the backend service for mobile applications used to serve requests, manage security and execute actions. Technically, it is a regular OData service (WCF Data Services 5.0) based on XPO OData V3 provider , XPO being the only currently supported ORM. Entity Framework (EF) and Domain Components (DC) support is not provided at the current stage of this product.
                                    3. MetadataService (MetadataService.svc) - this service supplies mobile application configuration data to a separate device simulator service.

                                    Q:  Does the new stateless architecture mean better scalability and thousands of users?
                                    A:  With the new architecture, an XafApplication instance with a cached state will not be stored in memory for each user as in the ASP.NET WebForms UI. Instead, a new instance will be created and released on each client request. As a result, memory requirements will be determined by the number of simultaneous requests and XAF application complexity rather than by the number of simultaneous users. This allows you to route client requests to different machines more easily  - easier horizontal scaling when compared to the older ASP.NET WebForms UI.
                                    However, processing each XafApplication instance may still take a good amount of memory in the case of complex XAF applications. As a result, thousands of simultaneous requests per second will unlikely be supported by this UI. High-load multi-tenant or SaaS Web apps that serve thousands of client requests imply different software architectures and budgets. A universal or general purpose framework  like XAF that costs a couple of thousand dollars would not be a good fit for such usage scenarios – you would have more success for enterprise tools optimized for such uses.
                                    Since most our Web and Mobile UI customers do not have more than 50 users according to their feedback (typically it is even less than 20-30 users), we also want to support a 'stateful' mode familiar to you by the existing ASP.NET WebForms UI. In this mode, it is possible that a database server will be hit less and overall performance may be better due to the in-memory cache. In stateful mode complex XAF apps can use vertical scaling to support more concurrent users.

                                    Q:  Will you support Xamarin?
                                    A:   Even though we are still tracking user interest in this regard, we do not have immediate plans to support it in XAF. Our current priority is to release the new UI for desktop Web and Mobile development first.  It’s simple - we (and I’d argue many of our users) prefer a single, unified development system. The Web is a common denominator that covers multiple platforms well. A reliable and modern Web solution is something most want/need to deliver and if one does a good job in this regard, a mobile solution should follow automatically (at almost no cost).  Promising technologies like React Native, Electron and WebAssembly could also give us expanded opportunities in the future to address the needs of those who prefer the “native” option. Xamarin did not meet this basic requirement and would have forced us to create separate solutions for the Web and Mobile (you would need investments for both Android and iOS platforms as well).

                                    Q: How can I deploy the mobile application to my production server?
                                    A: To deploy an XAF Mobile application to a public IIS server, you can use the same approach as those used to deploy XAF Web applications:
                                    Publish Web Deployment of an ASP.NET Application
                                    Xcopy Deployment of an ASP.NET Application

                                    Q: How can I build a native mobile package after I deployed the mobile application to my production server?
                                    A: Please refer to our online documentation describing how to accomplish this task: Install the Application to a Smartphone.

                                    Q: How to deploy mobile applications as regular web sites (disabled simulator and no PhoneGap)?
                                    A: This functionality is available by default - just open https://YourDomainName/Static/YourXAFVersion/player.html. For instance:
                                    To get this URL, scan the simulator's QR code or simply click it in your desktop web browser. If the index.html page (simulator) is opened from mobile devices, it will also redirect to player.html automatically.
                                    Note that our efforts have been focused on mobile devices so far. The application's UI is not adjusted for desktops and may have some visual artifacts that do not exist on devices.

                                    Q:  What are the currently supported XAF modules?
                                    A:  Full or partial support is available for the following XAF Modules.
                                        Security - end-user authentication takes place when the application starts and then every request checks user permissions before performing an operation. Known limitations are: no special editors for Criteria Properties, Protected Content and Navigation Permissions, custom values passed to these properties without any validation or formatting.
                                        Validation - if the module is included in the application as described here, then data is validated with every modification request to the backend server, prior to saving the changes. If possible, validation rules are moved to the client side so that they work without disturbing the backend service. For example, RuleRequiredField, RuleRange and RuleRegularExpression all work like that.
                                        ConditionalAppearance - you do not need to do anything besides what is described here  to activate this feature. Similarly to the Validation, the module functions on the client side if possible.
                                        FileAttachments  - downloading files only (see the instructions below for more details).
                                        ReportsV2  - downloading a report as PDF or other popular formats (see the instructions below for more details).
                                        Localization - automatically enables the appropriate UI language depending on the device settings.
                                        Maps - use instructions described here to activate this feature. It is required to specify the Google Maps API key to avoid runtime errors. Only raster maps are supported at the moment.
                                        Other platform-agnostic and platform-dependent modules - Chart, Dashboard, Pivot, AuditTrail, Scheduler, State Machine, Workflow, Notifications and other modules require further investigation. Key issues are screen size restrictions and native implementation of certain modules' functionality, Scheduler being a good example. It is likely that many of these extra modules will be unavailable for Mobile UI at all or to the extent it is available for other platforms. That is simply because copying the functionality for full-sized Windows desktop and Web browser apps "as is" does not make sense for small mobile and touch-enabled devices. Consult with the Extra Modules help topic for more details on the current state of support.

                                    Q: Can ALL the existing code base (such as ORM data model classes, Controllers and Application Model settings) be simply reused for the mobile UI with no changes?
                                    A: No, existing apps will require additional adjustments on your side to comply with the new UI concept and stateless service architecture.

                                    Q: Is UI customization done differently?
                                    A: Mobile UI is technically created once at design-time based on the ORM classes and consequently the Application Model settings. This process differs greatly from WinForms and Web UI where each View is created dynamically at runtime. Everything related to UI customization, UI interaction via Actions, conditional Appearance rules, and custom scripts should be created at design-time and packed into the mobile application. This way you can greatly reduce your web server load as well as dramatically minimize mobile traffic, which is essential for mobile devices.

                                    Q: Are standard and custom XAF Actions processed differently?
                                    A: Actions in mobile applications will work similarly to the Web by default. The app sends requests with all the information required to execute an action. At the same time, certain actions can be fully implemented on the client side. For example, actions which navigate between views don't require separate requests and thus can be fully processed on the client side. For example, you can navigate to the ProjectTask Detail View in the SimpleProjectManager-based mobile demo and then select 'Done!' from the menu. The status changes to Completed immediately on the client side. If you want to execute custom JavaScript code on the client side, use the RegisterClientScriptOnExecute extension method .

                                    Q: Are navigation items processed differently?
                                    A: Navigation items residing in custom navigation groups other than the "Default" one are not currently shown in the app. You will need to put all navigation items you would like to show into the Default group for now. In the future, it is possible that a different navigation control like Accordion will be introduced to cover complex navigation hierarchies.

                                    Q:  Can I use a calculated non-persistent property that depends on other business class values or runtime calculations?
                                    A: Non-persistent calculated properties declared using the DevExpress.Xpo.PersistentAlias, attribute or Custom Fields  operate as expected and do not require additional work on your side.
                                    Note that the DevExpress.Persistent.Base.ImmediatePostData attribute has a known limitation: in Mobile applications, non-persistent calculated reference properties are not updated.
                                    When the property is decorated with the ImmediatePostData attribute, the loading panel may be displayed when a user modifies a value.To improve UX in scenarios requiring calculated properties, we recommend that you move as much non-persistent properties calculation logic to the client-side as possible.

                                    Q:  Does this mobile application work offline? Or is it currently possible to store data locally on the mobile, if there is no internet connection?
                                    A: No, this feature is not currently available and is under consideration. We do not provide ready guidelines for accomplishing this task with our Mobile UI either. Our current thoughts on this scenario are given in the Proposed solution for offline application ticket. We would greatly appreciate it if you at least answer the two related questions:
                                    What is the minimum amount of features that should be supported in offline mode in your application?
                                    Is it sufficient to show cached data in read-only mode, or your users need a fully-functional application with the ability to create new objects and save changes?
                                    If you have more time, please comment on the additional considerations and possible implementation algorithm in our answer there. Thanks for your help in advance.

                                    Q:  Is there any internal backend API for accessing XAF data I can reuse with custom non-XAF clients?
                                    A:  Yes, and you can build a custom client application (hybrid or native, desktop or web, etc.) and connect it to the XAF OData service (DataService.svc). Technically, DevExpress.ExpressApp.DataService.dll provides the XafDataService<XafApplication>  class, which represents a standard WCF Data Service whose API conforms to OData V3. XafDataService currently supports only XPO and uses the XafApplication > ObjectSpaceProvider  property for connecting to your database, acquiring and modifying business objects. Additionally, the service reveals metadata information and supports the Basic authentication mechanism, which can be used by third-party application builders like Xamarin. For the security system to work, make sure your application uses SecuredObjectSpaceProvider.
                                    On the other hand, you can already reuse the existing XAF application data and certain logic without the XAF data service. See this support article  to estimate what is required to do this from scratch.
                                    NOTE: when using Basic authentication, you should consider encrypting communication between client and the data service by using the Secure Sockets Layer (SSL). Refer to the HTTPSWCF Data Services | Securing WCF Data Services and other public community resources for more details.

                                    Q:  How can I create and use the XAF secured OData Service supporting Basic Authentication with various clients?
                                    A:  Consider the following aspects:

                                    Service creation

                                    1. The simplest way is to reuse the DataService.svc file, which is automatically created by the XAF Solution Wizard when adding a mobile app into your existing XAF solution.
                                    2. You can also create such a service from scratch using the following steps:
                                    2.1. Invoke the Add | New Item... dialog to add a new "WCF Service"   item template called "TestDataService";
                                    2.2. Reference the DevExpress.ExpressApp.DataService.dll  along with an assembly with your XafApplication descendant  and then inherit the generated TestDataService class from the XafDataService one passing your XafApplication descendant type as a generic parameter:
                                    public class TestDataService : DevExpress.ExpressApp.DataService.XafDataService<AnyXafApplicationDescendant> { }

                                    2.3. Host the created service in a standalone ASP.NET application so that it is ready to serve requests from clients.

                                    Client-side usage
                                    Our mobile applications created via the XAF Solution Wizard can use such a data service automatically for getting and modifying data.
                                    The service uses the OData version 3 protocol:
                                     You can query this service using .NET, JavaScript and other clients according to the official OData v3 documentation ( and other public community resources.
                                    For instance, for .NET and JavaScript, use the approaches described at and respectively.

                                    Data service authenticates requests using the Basic Authentication protocol:
                                    In short, you need to add the Authorization field to the header of each request. For instance, if you are developing an HTML5/JavaScript client, you can use jQuery's beforeSend callback to add an HTTP header with the authentication information:

                                    beforeSend: function (xhr) { xhr.setRequestHeader ("Authorization", "Basic " + btoa(username + ":" + password)); }

                                    Refer to the documentation for each client-side technology for more details. In addition, check out the "Secured OData Service with Basic Authentication" section in this blog post for more examples.

                                    Q: Can we use third-party mobile controls or register custom JavaScript functions?
                                    A: Yes, see How to: Add an XAF Mobile Custom ModuleUPDATE:  With v19.1.5, the "XAF Mobile UI Custom Module" Item Template is removed from the Add New Item dialog. If you need it, download and extract the attached XAF_Mobile_UI_Custom file's content into the YourSolutionName.Mobile project.

                                    Q:  How do I diagnose the "Cannot load the application configuration. Error: ..." error when I run my mobile app?
                                    A:  Usually, it's difficult to determine the cause of this behavior by only the information displayed in this message box. The steps below will help you see the internal cause of this behavior, and, very often, guide you on how to fix the issue on your side yourself.

                                    1. In your Visual Studio, enable the "Common Language Runtime Exceptions"  option in the Debug | Exceptions menu item and disable the "Enable Just My Code"  option in the Tools | Options | Debugging menu item as described in the How to: Break When an Exception is Thrown MSDN article.
                                    2. Start the debugging and collect all uncaught or unhandled exceptions, and their stack traces (see the Call Stack window) as you debug the app (the debug output is not helpful for this task). Note that you may need to press the F5 (Continue) button after an exception was shown to collect details about next exceptions that do not allow your app to load. Note that certain exceptions can be safely skipped; e.g., UnauthorizedAccessException or CultureNotFoundException can be correctly handled inside the .NET libraries.
                                    3. If the additional error information does not help you overcome this problem on your side, please send us the full exception call stack and your debuggable project so we can also research this behavior locally.

                                    Q: Why does the Server Mode option have no effect when rows grouping is enabled in a List View?
                                    A:  Currently, partial data loading is not supported for grouped data in mobile applications, and there is no easy way to overcome this limitation. You can either show grouped records or use partial data loading, but not both features together.

                                    Q: How to localize an XAF Mobile application?
                                    A: Localization approaches described in the How to: Localize an XAF Application article are applicable to XAF Mobile applications. To enable the appropriate UI language automatically depending on the browser settings, include the Localization Module into the Mobile project.

                                    Q: How to integrate custom controls into an XAF Mobile application?
                                    A: Refer to the example provided in our online documentation demonstrating how to accomplish this task: How to: Add a button to a Form using Custom View Item.

                                    Q:   Can I use business objects mapped to database views or tables, whose primary key is composed of several columns?
                                    A:   No. You may receive the "The entity type 'XXX' does not have any key properties. Please make sure that one or more key properties are defined for this entity type. " error with OData Service (XpoDataServiceV3) if you map your persistent class to a table or view with a multi-column key. This configuration is not supported. Since the XAF Mobile UI uses XPO OData Service, this will not work there as well. In general, we do not recommend using composite keys as they impose many limitations on the default functionality. Refer to the How to create a persistent object for a database table with a compound key article for more details.

                                Show all comments
                                • Carlos Santillán León 04.21.2016


                                  I have a problem. I have installed VS 2013, .net framework 6.2 (ES) , but when I want to install XAFDataServiceCS.vsix i can't , it show me a message because i need to install a version which it is not installed in my computer.

                                  My question is: What framework I need to have installed in my computer? Thanks for your help

                                • José Enrique 04.22.2016


                                  You say that you are "considering offline feature" but let me tell you that it has no sense having a native hybrid app without offline capabilities because there aren't significant differences vs online web apps. In my opinion the business mobile challenge is developing native offline secured apps, so yes, this point is a must.

                                • Martin Praxmarer - DevExpress MVP 04.22.2016

                                  Same here - offline is a must have Feature for an business app!

                                • Dennis (DevExpress) 04.22.2016

                                  @Carlos: I've created a separate ticket on your behalf (T370776: Requirements for installing XAFDataServiceCS.vsix). It has been placed in our processing queue and will be answered shortly.
                                  @Jose, Martin: Thanks for your feedback.

                                • Paul Kubb 04.22.2016

                                  It is error today. Seems like you are developing it. (see attachment)

                                • Dennis (DevExpress) 04.22.2016

                                  @Paul: Yes, you just caught a two-minute interval when we were uploading the new version. It should be working now.

                                • Uros Rovtar 04.23.2016

                                  Please, think about Xamarin for XAF Mobile in the future...

                                • Franco Bonacchi 04.24.2016

                                  +1 Xamarin for XAF

                                • Dennis (DevExpress) 04.24.2016

                                  Thanks for your feedback, guys.

                                • Dennis (DevExpress) 04.24.2016

                                  @Uros, Franco: Would you please describe the key points of using Xamarin for building mobile applications over the hybrid HTML5/JavaScript/PhoneGap approach we are demonstrating here? It is likely the appearance of native controls + C#, but I would still love to hear a full list from you, guys. Thanks in advance!

                                • Alex Miller 04.25.2016

                                  @Uros & @Franco,

                                  If you could +1 the availability of DevExpress Xamarin controls... here:

                                • Rebecca Mergner 04.25.2016

                                  You guys do such amazing work. We have been entertaining how to get a XAF application rigged up in a mobile. this feature is going to be a god send.
                                  This is very exciting.
                                  Thank you for all the hard work you put into making this happen. 

                                • Dennis (DevExpress) 04.25.2016

                                  @Robert: Thanks for your feedback. Hopefully, you will have several minutes to complete the following survey so we can learn more about the types of application you’re looking to build with XAF mobile:

                                • Uros Rovtar 04.27.2016

                                  Of course It all depends how complex mobile app is and how much experience somebody has with technology. We are using .Net/Mono and C# for almost all the business apps and I
                                  cannot imagine using javascript as our (offline) code base. Currently Xaf Mobile is online oriented and I think you did great job regarding that. But sooner or later client wants offline mode with data synchronization... And here comes the local actions, background processing, async/await, linq, data signing with certificate, communication with POS printers , Bluetooth devices and overall access to all the native features....,with C# we could reuse our libraries....

                                  I think Xaf Mobile should next have offline mode ( local storage, local actions) , we should also decide on the server side , which BO ( base code tables like person,post,country etc.) should be synced, which non persistent objects should be available and posibility to call any custom server side defined controller method....  What about clever controller, which is shared by mobile and server, when running in local context, data is persisted to local storage and the synced with server....
                                  i think this kind of code reuse is possible only with the same language and libraries, so +1 for .Net Core / Mono / Xaf / Xamarin, and Xpo for Xamarin :)

                                • Dennis (DevExpress) 04.28.2016

                                  @Urus: Thanks a lot for your explanation and suggestions.

                                • LeventUysal 05.04.2016

                                  I've created a new XAF Project (ver.15.2.9) and added a XAFDataService project. But, Project.Module component do not seem in MobileApplication's toolbox. How can I do?

                                • Dennis (DevExpress) 05.04.2016
                                • HENRY HAGE 05.10.2016

                                  I am testing this application on my android mobile , I am facing an issue while connecting to my database :
                                  'listViewDataSource' data source error: Unspecified network error (if the remote host is located on another domain, make sure
                                  it properly supports cross-origin resource sharing ....or use JSONP approach instead)

                                  Note:I am connecting to a database located on Microsoft azure.
                                  Do you have a solution for this problem ?

                                • Dennis (DevExpress) 05.10.2016

                                  @HENRY: I've created a separate ticket on your behalf (T377080: 'listViewDataSource' data source error: Unspecified network error). It has been placed in our processing queue and will be answered shortly.
                                  Please submit separate tickets  for each problem or question for better tracking. Thanks in advance.

                                • Mario Blatarić 05.24.2016

                                  +1 for Xamarin and XAF.

                                  I will just re-quote Uros:
                                  "... local actions, background processing, async/await, linq, data signing with certificate, communication with POS printers , Bluetooth devices and overall access to all the native features... "

                                  HTML5/JS is nice for presentation stuff, but when you want to implement certain business processes you just cry for C# and .NET

                                  Personally, I will be more than fine with current mobile implementation for some time as I mostly need mobile version for presentation and some basic data entry and I think current version is amazing addition to XAF ecosystem - world is moving quickly on mobile devices and having proper support in tools is extremely important.
                                  I am grateful DevExpress is recognizing this and moving things in the right direction. Since XAF is mostly business oriented, I think merging XAF and Xamarin would be great in future versions of the product (especially now when MS purchased Xamarin and made it integral part of VS).

                                  Best regards,

                                • Dennis (DevExpress) 05.24.2016

                                  @Mario: Thanks for your comments too - we greatly appreciate this

                                • Miles 05.24.2016

                                  +1 for Xamarin and XAF 

                                • Amin Baig 05.24.2016

                                  I have to agree with Uros.

                                  Anyone working with enterprise application will need an offline mode for data, local actions etc. with this, it would be impossible to put out an application which is field friendly for the sales force or any such people.

                                  Also, I wanted to ask, in the last release of Xaf for mobile, we had to use phonegap to build our app. Is it still the same? If so, can we expect this dependency on building externally to be removed?

                                • Willem de Vries 05.24.2016

                                  I agree with Mario.

                                  And i have the same PhoneGap question as Amin.

                                  +1 for Xamarin and XAF

                                • Maxime MERIAUX 05.24.2016

                                  Totally agree with Mario aswell :)

                                  +1 for Xamarin and XAF

                                • Dennis (DevExpress) 05.25.2016

                                  >>Also, I wanted to ask, in the last release of Xaf for mobile, we had to use phonegap to build our app. Is it still the same? If so, can we expect this dependency on building externally to be removed?
                                  @Amin, Willem: Yes, you need to use the service for now. Our team will take your suggestions into account for the future. Thanks.

                                • MichailTemelkos 05.29.2016

                                  +1 for Xamarin and XAF 

                                • Elias Sparagis 06.02.2016

                                  Hello DX,

                                  I'm trying to evaluate the xaf mobile UI but I got an IIS Express error .

                                  What have I missed?

                                  Please see the attached image.

                                  Thank you,
                                  Elias Sp.

                                • Dennis (DevExpress) 06.02.2016

                                  @Elias: I've created a separate ticket on your behalf (Unable to launch the IIS Express Web server). It has been placed in our processing queue and will be answered shortly.
                                  For the future, please submit separate tickets  for each problem or question for better tracking. Thanks in advance.

                                • Elias Sparagis 06.02.2016

                                  Please accept my apologies.

                                  Thank you.

                                • Dennis (DevExpress) 06.02.2016

                                  @Elias: No worries

                                • Customer116545 06.09.2016

                                  Hi I'm getting following error:
                                  Cannot load the application configuration. Error:

                                  <!DOCTYPE html>



                                          <title>The resource cannot be found.</title>

                                          <meta name="viewport" content="width=device-width" />


                                           body {font-family:"Verdana";font-weight:normal;font-size: .7em;color:black;}

                                           p {font-family:"Verdana";font-weight:normal;color:black;margin-top: -5px}

                                           b {font-family:"Verdana";font-weight:bold;color:black;margin-top: -5px}

                                           H1 { font-family:"Verdana";font-weight:normal;font-size:18pt;color:red }

                                           H2 { font-family:"Verdana";font-weight:normal;font-size:14pt;color:maroon }

                                           pre {font-family:"Consolas","Lucida Console",Monospace;font-size:11pt;margin:0;padding:0.5em;line-height:14pt}

                                           .marker {font-weight: bold; color: black;text-decoration: none;}

                                           .version {color: gray;}

                                           .error {margin-bottom: 10px;}

                                           .expandable { text-decoration:underline; font-weight:bold; color:navy; cursor:hand; }

                                           @media screen and (max-width: 639px) {

                                            pre { width: 440px; overflow: auto; white-space: pre-wrap; word-wrap: break-word; }


                                           @media screen and (max-width: 479px) {

                                            pre { width: 280px; }




                                      <body bgcolor="white">

                                              <span><H1>Server Error in '/' Application.<hr width=100% size=1 color=silver></H1>

                                              <h2> <i>The resource cannot be found.</i> </h2></span>

                                              <font face="Arial, Helvetica, Geneva, SunSans-Regular, sans-serif ">

                                              <b> Description: </b>HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable.  Please review the following URL and make sure that it is spelled correctly.


                                              <b> Requested URL: </b>/MainDemoMetadataService.svc/AppConfig<br><br>



                                • Dennis (DevExpress) 06.09.2016

                                  I've created a separate ticket on your behalf (Cannot load the application configuration. Error:). It has been placed in our processing queue and will be answered shortly.

                                  For the future, please submit separate tickets via the service  for each problem or question for better tracking instead of leaving comments in this KB article. Thanks in advance.

                                • DEEPAK CHAVAN 06.21.2016

                                  XAF on mobile will be excellent move. Please make UX enhancements something
                                  Give ability to set UI fields as per database size
                                  Give ability to do more client side validation like numbers range

                                  Offline is must have feature I have seen user use it less but its first demand.
                                  Then auto sync data between offline and online db

                                  Thanks and Regards
                                  Deepak Chavan, PMP

                                • Dennis (DevExpress) 06.21.2016

                                  @DEEPAK: Thanks for your suggestions. Our team will take them into account.

                                • Bjoern Isemann 06.22.2016

                                  Its a perfect solution for a  new project i just got. nevertheless, offline database is a must for us. We need to sync the data with our database server via OData while having WLAN and work offline when using the device offsite where no access to the intranet is possible and allowed. Finally, when WLAN is available again, the data needs to be uploaded via action to the server.

                                  It shouldnt be a big issue to build this functionallity if i can use local databases on the device, like microsoft sql compact etc. :-)

                                • Willem de Vries 06.22.2016

                                  Take a look at Microsoft's Synchronisation Framework:

                                • Dennis (DevExpress) 06.22.2016

                                  @Bjoern  and Willem: Thanks for your comments.

                                • Hans Rutstrom 06.28.2016

                                  This looks great and a much appreciated addition to the XAF eco system.

                                  Just a question though. Does things like automatic invokation of workflow instances work with the mobile/dataservice solution? Say you have a workflow set up to trigger when a particular business object is created, will this work when the object is created from a mobile device?

                                • Dennis (DevExpress) 06.28.2016

                                  @Hans: Thanks for your feedback. I've created a separate ticket on your behalf (T397363: Will a workflow definition with AutoStartWhenObjectIsCreated = True still be triggered when target data records are created by external code directly in the database?), and it has been placed in our processing queue.
                                  For the future, please submit separate tickets via the service  for each problem or question for better tracking instead of leaving comments in this KB article. Thanks in advance.

                                • James S K Makumbi 09.18.2016

                                  Hi, I notice you have removed the CTP from 15.2.12 (or earlier).
                                  The only way to get to use this is with 16? This was an unusual workflow (add a feature then remove it) but I understand.

                                • Dennis (DevExpress) 09.19.2016

                                  @James: The mobile UI (CTP) functionality prior to the v16.1 release was distributed as part of a demo application that could be installed by interested users manually in their Visual Studio via the VSIX template. It has never been a part of the main product before, so there is nothing to remove here. Our first public preview in v15.2.9 was primarily targeted to collect opinions from a large audience on the direction we are moving on with this feature, which was not yet supposed to be used in production. Previously (December 2015), we ran a private preview for just a hundred of users for the same exploration purposes.
                                  So, to answer your question directly: yes, it is now recommended to install the XAF v16.1+ (registered or trial) and follow the Getting Started > XAF Mobile (CTP) Tutorial tutorial to explore this CTP feature. As an exception, I can obtain the old VSIX demo we provided in the past for you, but we no longer provide a tutorial/support for that old version + the supported functionality has greatly changed in certain aspects.

                                • Farooq 01.03.2017

                                  Hi Dennis

                                  Last time when I tried the XAF mobile CTP release I found that server URI was hard coded in the package. I would like to check whether this issue is resolved or not. In One of the comments I noticed that URI of the production server is now being packaged with the app but my scenario is that I have several clients who are running my XAF and if I have to provide them with a mobile app then how can I package it without any URI and let the user selects/types the URI on his app and then the app connects to the corresponding server. 

                                • Uriah (DevExpress Support) 01.04.2017

                                  Hi Mohammed,

                                  I've created a separate ticket on your behalf (T468469: Can I connect an XAF Mobile application to an arbitrary service?). It has been placed in our processing queue and will be answered shortly.

                                • Roman Shelomanov 02.07.2017

                                  Looks like a good start to move ASP.NET client to HTML5 also,

                                • Norbert K. 04.04.2018

                                  +1 for Xamarin and XAF

                                • Dennis (DevExpress) 09.20.2018

                                  Hello everyone!

                                  I wanted to share our updated vision for XAF Web & Mobile development – one that’s based on an entirely new SPA driven UI. When this ASP.NET Core and React-based solution matures, it will supersede/replace existing WebForms and Mobile user interfaces.

                                  Right away, existing XAF Mobile UI users are welcome to migrate to our newest server features: How to connect an existing XAF Mobile application to the new ASP.NET Core Data Service (CTP). The new SPA UI will use this server and you can help us release this portion faster by providing feedback.
                                  We hope to publish new SPA UI demos online after our v18.2 release. In the meantime, anyone is welcome to check screenshots of our prototypes and discuss their specs in our forum with peers. No promises at this stage, but our hope is to offer this SPA UI for production use around the v19.1 timeframe (at least for simple scenarios).


                                • Scott Gross 09.26.2018

                                  ok, looks like it's time to start learning React!

                                • Dennis (DevExpress) 09.26.2018

                                  >> ok, looks like it's time to start learning React!
                                  @Scott: Our target audience is mostly C#/VB .NET developers. The majority of existing XAF users does not often make complex customizations of underlying controls and the rest infrastructure. Since the framework generates the UI transparently and you also have a high-level control over it using the Model Editor or attributes, we hope that React knowledge will not be needed much (at least for the majority of our users). APIs that we will provide to SPA UI developers for client-side customizations will be transparent and client-side framework agnostic anyway.

                                • Dennis (DevExpress) 03.15.2019


                                  We have published an early preview v19.1 build and updated this KB article so that you can learn more about the new SPA UI development. You can also discuss it with other XAFers on the private forum if you wish.
                                  For more information on features that you can expect in v19.1, check out these blog posts.


                                • Akin GUNES 03.15.2019

                                  Hi Dennis,
                                  I think it is time to split this SPA UI and old Mobile UI part into seperate articles. 

                                • Stanislaw.Tristan 05.22.2019

                                  What about Blazor? I understand that currently it is in a preview, but interest to know - if the Blazor development and support trends will grow - is it a possibility for implementation of future versions of SPA with it?

                                • Dennis (DevExpress) 05.22.2019

                                  @Stanislaw.Tristan: Blazor is a very interesting direction, and we are researching it. For instance, other DevExpress teams published control previews: You can also check out my non-XAF example for XPO with Blazor:
                                  At this stage, we are not ready to discuss XAF Blazor UI or any time frames, mainly because the new tech is still raw. Right now, we continue our SPA UI (CTP) development according to our initial plan.

                                  In that respect, how important is it for you to use Blazor, React or another tech under the hood as long as the Web app does what your clients want? If you already experimented with Blazor and can share your thoughts on how it compares to other Web tech, we will be more than happy to hear from you.
                                  From the developer prospective, C# may be a more preferred choice, but Blazor does not save your from JavaScript completely. And like with the former ASP.NET WebForms UI, with SPA UI our users may want to use JavaScript only for some advanced customizations.

                                • Stanislaw.Tristan 05.22.2019

                                  @Dennis. I'm not using Blazor (and even have not tested it). But I watching it in context of support by component vendors like Devexpress. I believe that your SPA implementation will be powerful and cover most business scenarios. But in the case when we need to implement some customization (currently this is often my use case in XAF WinForms) and my customers will decide to switch from WinForms to SPA - I will prefer to use as match of C# as possible to perform the migration of custom controls.

                                • Dennis (DevExpress) 05.22.2019

                                  @Stanislaw.Tristan: Thank you for sharing your thoughts.

                                • Dennis (DevExpress) 06.05.2019


                                  What would you prefer or how do you feel (and why?) if you face the following choice today:
                                  1.  Wait 1 year for a stateless XAF React and ASP.NET-based UI. Its client-server architecture would differ a lot from WinForms. Custom tasks and control customizations would often require good Web technology knowledge (modern JavaScript, HTML, CSS, ASP.NET Core, etc.).
                                  2.  Wait 2 years for a stateful XAF Blazor-based UI (server-side hosting model) with a potential for offline support with WebAssembly in the far future. Custom tasks and control customizations would likely require only C#/VB.NET or a minimal Web technology knowledge.

                                • Martin Brekhof 06.05.2019

                                  Option 2 with the timeline of option 1 :-)
                                  As I am currently doing all mobile development in Xamarin I am mainly interested in creating administrative backends and or BI tools (reporting/pivot tables etc.). Blazor seems to perform exceptionally well performance wise so that would have my preference.


                                • Paul Kubb 06.05.2019
                                  1. seems more scalable, but i believe it will be a mess and buggy due to the very different architecture. if i had choices i would rather not use it.
                                  2. seems to be easier in transformation for both of us. while scalability is still in question. but i believe it will be better than traditional also your already superb components such as gridcontrol or pivotgrid will be the same so no need to mess with project migration.

                                  i go for 2.

                                • José Enrique 06.05.2019

                                  Without doubting I would choode first approach. It is stateless which means scalability, probably a better UX and definetly a jump towards cloud. It Is just where LOB applications should be, and of course this deserves an efford if we want to develop quality web applications.

                                • Pawel Botwina 06.05.2019

                                  Option 2.
                                  Time will always pass ...

                                • Dave Hesketh (Llamachant Technology) 06.05.2019

                                  Option 2. I really like the idea of scalability in option 1 but I'd rather not endure the hassle of creating new editors and templates using a broken technology (JavaScript to Browser).

                                  Also, the idea of offline support down the road is HUGE.

                                • Marco Kummer 06.05.2019

                                  Option #1, preferrably with VueJs instead of React, as Vue is growing faster and follows a cleaner approach and is less JS focused.

                                  As for option 2, I‘d like to remind everyone here that Microsoft once promised Silverlight to be the next holy grail in web development. I think it‘s fair to assume that even DX made losses with all their silverlight components. So I think it‘s time we embrace the fact that web development uses different paradigms than the C# world. We should not fight against this fact, but instead make it our friend. If you really need the comfort of C#, I recommend It doesn‘t lock you in the way Blazor does.

                                • Pietro Allegretti 06.05.2019

                                  Option 2 for me, but you should make a convincing work in the cloud ready direction.

                                • Chris Royle (LOB) 06.05.2019

                                  Marco Kummer makes a good point.

                                  Being an optimist I'd say option 2 - as this would also allow for some early influence in the development of the DX Blazor component suite.

                                • Dennis (DevExpress) 06.05.2019

                                  My team and I appreciate your thoughts, Guys. As for scaling and clouds, you may find this information from Dan Roth interesting:
                                  "WebSockets are required when publishing a server-side Blazor app. Publishing a server-side Blazor app to Azure App Service should work fine today as long as you do a self-contained deployment. However, we also recommend using the Azure SignalR Service with server-side Blazor apps, which should remove the need to enable WebSockets and will dramatically improve the ability of your app to scale out.".

                                • Randy Jean 06.05.2019

                                  As of today, I would choose Option 2 only because we have no pressing need for mobile XAF apps today that we can't achieve with the New Web UI theme with mobile layouts (assuming requirements are simple and a mobile web app is acceptable)

                                • Bassam Abdelaal 06.06.2019

                                  Option 2 is more preferable because :
                                  Its more natural for .net developers (C# , .Net), XAF Blazor controls customization will be much easier and faster for developers and also – I guess -  even easier for DevExpress to produce examples , how tos , much less support tickets than a pure JS/HTML/CSS version of controls
                                  We have no immediate must have mobile version, can wait , since option 1 & 2 will need sometime anyway then better to wait for the more convenient output , meanwhile current XAF web is very good enough with many options and new editors produced
                                  Blazor is not like Silverlight , WebAssembly is a consensus standard this time , Microsoft , Google , Mozilla and others are strongly embracing it , its not a plugin and it runs in major browsers
                                  Clearly Blazor will have a huge impact , most are very interested about it, see what DX did in even a pre 1.0 version and other third party control vendors are doing , currently preparing for version 1.0 , progress in feature list will come so fast from DevExpress clearly satisfying the need for XAF Blazor
                                  Promising future implementations like offline with WebAssembly makes it even more interesting , So we very much hope it can be XAF Blazor instead of XAF JS

                                • Alexander Krakhotko (Xafari team) 06.06.2019

                                  'm for Option 1 - web application scalability is very important to us (1000+ users)
                                  option 2: two years is a very long time for us, but when it comes we migrate to simplify development projects

                                  Now we are creating our "xafari-html5-client" because of the need to have one client for XAFapps and not-XAF applications (delphi, c++ etc) (one client for different applications)

                                • Martin Praxmarer - DevExpress MVP 06.06.2019

                                  "xafari-html5-client - that sounds interessting - do you have further details on this? 

                                • Stanislaw.Tristan 06.06.2019

                                  Option # 2, as I have already mentioned in my comment above

                                • mgc 06.06.2019

                                  option #1
                                  For us, top priority for the web applications is performance and UI customisation. That is why we use XAF for Windows and ASPNETZero for Web apps.

                                • José Enrique 06.06.2019

                                  Hi mgc, have you managed ASPNETZero or ABP with XPO in order to reuse XAF BO model?

                                • Alex Miller 06.06.2019

                                  @Dennis Can you share the link to the repo of the test BlazorXAFSolution teased in the screenshot?

                                • Alexander Krakhotko (Xafari team) 06.06.2019

                                  Martin Praxmarer: we do not have a public version yet. plan by the end of the 2019 year

                                • Dennis (DevExpress) 06.09.2019

                                  @Alex Miller: Not in public at this stage (check your email).

                                • Eric Upton 06.13.2019

                                  #2 - Blazor
                                  In my limited understanding of WebAssembly and Blazor, it feels like this will be the future model for web dev. I'm certain the html, javascript, and css model will likely be around for a very long time, but I feel like the WebAssembly approach is the next major evolution. We're C#/.Net developers. It will be much better to program and customize in C#/.Net
                                  Javascript requires framework on top of framework to make it behave and function the way we need for modern apps. And it is still awful.
                                  A few concerns with Blazor/WASM:
                                  1. Will it go the way of Silverlight?
                                  Reasons I don't think Blazor will die off like SilverLight
                                  It is Open Source
                                  Doesn't require any special plugins to run on client/user side (WASM is currently supported in all modern browsers)

                                  2. In my opinion Blazor and WASM are not yet mature, and may not support all expected features of a modern web app
                                  it's only a matter of time. Especially now with Microsoft going full steam ahead with Blazor, I believe WASM will grow even more.
                                  3. Are we asking WASM to do something it wasn't intended to do?

                                  Time will tell, but I think we've done much worse by making javascript do what it was never intended to do. In my opinion this will be a much more robust solution.
                                            4. Stateful/Stateless architecture
                                  This is my biggest concern regarding Blazor and one of the things I like most about your current progress with the SPA UI. Scalability will be more of a challenge with Blazor using a Stateful arch, but it's something I can live with for my typical Line of Business App.

                                • Decoder4 06.30.2019

                                  I am very curious about the outcome of your research regarding # 1 and # 2. Our preference is # 1 based purely on speed and proven technology. xaf has been lagging behind the web environment for years and constantly changing technology offers us too much uncertainty.

                                • Scott Gross 06.30.2019

                                  Agreed, #1

                                • Casey Chester 07.16.2019

                                  #2 Blazor.
                                  Look at it from the perspective of many of your existing customers that are using XAF primarily for developing exactly what XAF was originally designed for - enterprise applications. To date, they have done this with WinForms and WebForms, both of which allow 99.999% XAF customization's to performed in a .NET language. DX should not underestimate the huge value proposition this poses to many small to medium sized businesses with limited budgets for custom enterprise application development.

                                  Now you are telling these same customers that the future of XAF on the web is focused on MANY non-.NET languages/technologies. It just seems to me that Blazor/WASM would allow DX to deliver the improvements some customers require while staying true to customers that selected XAF primarily for the value proposition described earlier.

                                  Besides, there is a good chance in two years time React will have completely fell out of favor for the next newest framework or technology, which may very well be Blazor.

                                  If I were XAF product manager, it seems like an easy decision to me.

                                  My $0.02 worth.

                                  Casey Chester 

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