Improve ListViewSubItem.Text performance

[elachlan]

Fixes #10963

Change ListViewSubItem.Text to pass index to ListViewItem.UpdateSubItems to avoid loop.

Microsoft Reviewers: Open in CodeFlow

[elachlan]

@Olina-Zhang can your team please test this?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 74.26543%. Comparing base (0aa3a4d) to head (e2da404).

Additional details and impacted files

@@                 Coverage Diff                 @@
##                main      #11401         +/-   ##
===================================================
+ Coverage   74.26256%   74.26543%   +0.00287%     
===================================================
  Files           3025        3025                 
  Lines         626861      626861                 
  Branches       46742       46742                 
===================================================
+ Hits          465523      465541         +18     
+ Misses        157993      157977         -16     
+ Partials        3345        3343          -2     

Flag	Coverage Δ
Debug	74.26543% <100.00000%> (+0.00287%)	⬆️
integration	17.99452% <12.50000%> (-0.00141%)	⬇️
production	46.99221% <100.00000%> (+0.00630%)	⬆️
test	96.98684% <ø> (ø)
unit	43.94371% <100.00000%> (-0.02247%)	⬇️

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[Olina-Zhang]

Hi @elachlan, tested before and after this PR change, I didn't see any behavior difference when updating one ListViewSubItem's Text property, noticed entire row is blinking once(The recorded video doesn't seem to show it), is it the issue? Not sure if I understand the client's question correctly.

ListViewSubItem.sText.mp4

[elachlan]

Hi @Olina-Zhang, That is fantastic. There shouldn't be any behavior changes.

The issue will arise if there is a large number of sub items (1000) it will be very slow to update. After the change it should be very quick.

[Olina-Zhang]

That's because my test was a bit small, I'll try a bigger one.

[Olina-Zhang]

If ListView has a large number of sub items (>1000), updating the text of ListViewSubItem is also quite fast with before and after your PR change, looks like no difference.

LargeListViewSubItem.sText.mp4

[Tanya-Solyanik]

The change looks reasonable. Probably updating text for all subitems was an oversight in the original implementation.

[John-Qiao]

Verified this issue on 9.0.100-preview.5.24273.4 with dlls built from winforms repo of main branch, the result is same as above which Olina did.

11401-testresult.mp4

[John-Qiao]

Verified this issue with 9.0.100-preview.5.24304.3 test pass build, it was fixed. Test result is same as above.