Test if listbox has any items before invoking listBox.Items[e.Index] in ListBoxes.cs of the WinformsControlsTests

[LeafShi1]

Fixes #13047

Proposed changes

• Add a logical judgment before invoking listBox.Items[e.Index] in ListBox_DrawItem method in ListBoxes.cs of the WinformsControlsTest application to prevent the exception

Customer Impact

• The click event can be done normally on ListBox

Regression?

• No

Risk

• Minimal

Screenshots

Before

Clicking on ListBox Drawmode.OwnerDrawFixed and ListBox Drawmode.OwnerDrawVariable brings up the exception error window in the WinformsControlsTest application

After

Everything work well on ListBox

Test methodology

• Manually tested the application

Test environment(s)

• .net10.0.0-preview.3.25155.12

Microsoft Reviewers: Open in CodeFlow

[Epica3055]

looks good

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 61.28152%. Comparing base (6061b98) to head (a890fee).
Report is 8 commits behind head on main.

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #13106         +/-   ##
===================================================
- Coverage   61.28468%   61.28152%   -0.00317%     
===================================================
  Files           1541        1541                 
  Lines         158281      158281                 
  Branches       14743       14743                 
===================================================
- Hits           97002       96997          -5     
- Misses         60581       60586          +5     
  Partials         698         698                 

Flag	Coverage Δ
Debug	61.28152% <ø> (-0.00317%)	⬇️
integration	10.73877% <ø> (+0.00105%)	⬆️
production	39.14705% <ø> (-0.00519%)	⬇️
test	95.67280% <ø> (ø)
unit	36.56971% <ø> (-0.00521%)	⬇️

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[Tanya-Solyanik]

Thank you!