Starting with version 13.2, the ASPxGridView control offers the basic "Batch Editing Mode" functionality that allows accomplishing a similar task with less effort and does not require so much extra code. See the ASP.NET WebForms & MVC: GridView Batch Edit blog post to learn more about this new functionality.
Starting with version 14.1, the ASPxGridView control offers advanced "Batch Editing Mode" programming options.
You can find a standalone DB-independent solution in our Code Examples base at:
ASPxGridView - A simple Batch Editing implementation
If you have version v14.1+ available, consider using the built-in functionality instead of the approach detailed below.
If you need further assistance with this functionality, please create a new ticket in our Support Center.
Custom logic implemented in this example allows the end-user to select a limited number of named columns via comboboxes. The maximum number of columns the user can select is defined by a numeric column value, which he can also change. The only callback is used to post the entire grid page data.
To work in multi-row-edit mode, scripts and ClientInstanceName property values are generated programmatically.
ASPxGridView - Multi-Row Editing
How to implement the multi-row editing feature in the ASPxGridView
How to perform ASPxGridView instant updating using different editors in the DataItem template