Change DataGridView.GridColor when set.

[JeremyKuhne]

Actually change the GridColor when set. Add a test for GridColor.

Fixes #3829

Proposed changes

• Fix missing property set

Customer Impact

• Can't set the grid color without this change

Regression?

• Yes

Risk

• Very low

Screenshots

Before

See #3829, grid was black.

After

Test methodology

• Add test for property
• Validate visually in WinForms app
• Examine GDI calls involved (Tests for the calls forthcoming, need to fill out the emf validation more. The records are a bit complicated as we're using GDI+ to draw the grid and it uses transforms and polylines to draw)

Microsoft Reviewers: Open in CodeFlow

[JeremyKuhne]

When looking at how the drawing is happening here we could easily get some perf here by switching from GDI+ to GDI for drawing gridlines. Unfortunately the model publicly passes Graphics so we'd have to do some contortions to have an optimized path.

[KlausLoeffelmann]

Looks good to me!

[codecov]

Codecov Report

Merging #3869 into master will increase coverage by 30.60438%.
The diff coverage is 100.00000%.

@@                 Coverage Diff                  @@
##              master       #3869          +/-   ##
====================================================
+ Coverage   67.52959%   98.13397%   +30.60438%     
====================================================
  Files           1400         481         -919     
  Lines         505876      255248      -250628     
  Branches       41086        4295       -36791     
====================================================
- Hits          341616      250485       -91131     
+ Misses        158329        4035      -154294     
+ Partials        5931         728        -5203     

Flag	Coverage Δ
#Debug	98.13397% <100.00000%> (+30.60438%)	⬆️
#production	?
#test	98.13397% <100.00000%> (-0.00776%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

[JeremyKuhne]

Release build tests failed with an odd AV (unrelated to this change). I'm looking into it, rekicking.