Invoking the CheckedListBoxControl.SetItemChecked method passing a negative index as parameter will throw ArgumentOutOfRangeException[C#]
The method should have no effect, and no exception should be thrown.
As stated in the documentation, for the index param:
"An integer value representing the zero-based index of the item to be changed. If it is negative or exceeds the last available index, the method will have no effect."
Thank you for your patience.
This is the expected behavior. Starting with version 12.1.5, ArgumentOutOfRangeException is thrown in this case. This allows you to handle it and prevent unexpected behavior in your project.
We will correct the SetItemChecked article in our documentation accordingly.