winforms Fix: Hide 'Edit Items...' when ListBox DataSource is set

Fixes #14063

Proposed changes

Modified ListControlUnboundActionList to hide "Edit Items..." action in smart tag when DataSource is set
Added custom ItemsPropertyDescriptor in ListBoxDesigner to remove editor from Properties window when DataSource is set
Updated ListControlUnboundActionListTests to verify action is shown/hidden based on DataSource state
Reverted initial exception handling approach based on feedback

Customer Impact

Users will no longer see the "Edit Items..." option in the smart tag or Properties window when a ListBox has a DataSource bound
Prevents users from attempting an invalid operation that would fail
Provides better UX by making invalid states unavailable rather than showing error messages after the fact
Aligns with .NET Framework 4.8.1 behavior where "Edit Items..." was not shown for data-bound ListBox

Regression?

No - improves UX by preventing invalid operations, does not change behavior of valid scenarios

Risk

Low - changes only affect UI availability when DataSource is set, does not alter any functional behavior when DataSource is null

Screenshots

Before

"Edit Items..." appears in smart tag and Properties window even when DataSource is set, clicking it shows error:

After

"Edit Items..." is hidden when DataSource is set (no action shown in smart tag, no editor link in Properties window):

Test methodology

Added unit test GetSortedActionItems_ShouldReturnEmpty_WhenDataSourceIsSet to verify smart tag action is hidden when DataSource is set
Updated existing test GetSortedActionItems_ShouldReturnCorrectItems_WhenDataSourceIsNull to verify action appears when DataSource is null
Manual test: DemoConsole app → TabPage5 → Select ListBox with DataSource → Verify "Edit Items..." is not shown in smart tag or Properties window
Verified non-data-bound ListBox (TabPage2) still shows "Edit Items..." and opens collection editor normally

Test environment(s)

.NET 10.0 SDK (version: 10.0.100-rc.2.25502.107)
Windows 11
Visual Studio 2022

Original prompt

This section details on the original issue you should resolve

<issue_title>DemoConsole app: Unexpected warning pops up when clicking 'Edit Items...' command link for ListBox in Properties window</issue_title> <issue_description>### .NET version

main branch of Winforms repo

Did it work in .NET Framework?

Yes

Did it work in any of the earlier releases of .NET Core or .NET 5+?

No, still repro in Release/9.0 branch when ListBox was added in DemoConsole app, no this control in DemoConsole app on Release/8.0 branch

Issue description

In DemoConsole test app of WinForms repo, unexpected warning pops up when clicking 'Edit Items...' command link for ListBox in Properties window

Expected Result: for clicking Items property

In .NET framework 4.8.1 for DemoConsole app, there hasn't 'Edit Items...' command link for ListBox in Properties window

Steps to reproduce

Test the sample app: DemoConsole in Winforms repo, go to TabControl and TableLayoutPanel page to find ListBox control</issue_description>

Comments on the Issue (you are @copilot in this section)

Fixes dotnet/winforms#14063

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Nov 19 '25 21:11 Copilot

Codecov Report

:x: Patch coverage is 90.47619% with 2 lines in your changes missing coverage. Please review. :white_check_mark: Project coverage is 97.40709%. Comparing base (7758e7d) to head (818aa0a).

Additional details and impacted files

@@                 Coverage Diff                  @@
##                main      #14065          +/-   ##
====================================================
+ Coverage   77.15867%   97.40709%   +20.24841%     
====================================================
  Files           3279        1214        -2065     
  Lines         645317      357397      -287920     
  Branches       47718        5599       -42119     
====================================================
- Hits          497918      348130      -149788     
+ Misses        143692        8473      -135219     
+ Partials        3707         794        -2913

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Debug	`97.40709% <90.47619%> (+20.24841%)`	:arrow_up:
integration	`?`
production	`?`
test	`97.40709% <90.47619%> (-0.00040%)`	:arrow_down:
unit	`?`

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Nov 19 '25 22:11 codecov[bot]

Tested this PR change, the error message is correct, but dialog title and icon are not correct. It also change the message for clicking 'Edit Items' in smart tag window. 'Edit Items' in smart tag window: 'Edit Items...' command link in Properties window: Items property in Properties window: - no affect

Nov 20 '25 01:11 Olina-Zhang

@copilot With the DataSource already set, the Edit Item... should not be displayed. Therefore, the solution is to hide the Edit Item... in the smart tag window and property page when the DataSource is already bound.

Nov 24 '25 08:11 LeafShi1

@copilot With the DataSource already set, the Edit Item... should not be displayed. Therefore, the solution is to hide the Edit Item... in the smart tag window and property page when the `DataSo...

You're absolutely right! I've updated the solution to hide the "Edit Items..." option when DataSource is set, instead of showing an error message. The changes include:

Smart Tag: Modified ListControlUnboundActionList to conditionally show the action only when DataSource is null
Properties Window: Added custom ItemsPropertyDescriptor that removes the editor when DataSource is set

The fix is in commit 9b0328e.

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Nov 24 '25 08:11 Copilot

@copilot Now the "Edit Items" in Smart Tag window is removed when binding data Source for ListBox and the "Edit Items..." command link is removed too in Properties window. But the Items property behavior in Properties windows is not correct, it should pop up an error instead of opening Object Collection Editor dialog when binding data source, keeping the previous behavior. Now: click Items property behavior:

Nov 24 '25 08:11 Olina-Zhang