BackColor and ForeColor in DrawListViewColumnHeaderEventArgs have alpha component set to 0

[anders9ustafsson]

.NET version

.NET 8.0

Did it work in .NET Framework?

Yes

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

No response

Issue description

In our code, we are using the OwnerDraw mode for System.Windows.Forms.ListView. When accessing the ForeColor and BackColor properties of DrawListViewColumnHeaderEventArgs, we notice that the alpha component of respective color is 0, although we would have expected 255. Therefore, e.g. when drawing text using ForeColor, no text can be seen in the header.

Looking at the source code where DrawListViewColumnHeaderEventArgs is defined in ListView, I notice that the colors are obtained using P/Invoke methods GetTextColor and GetBkColor, respectively:

Color foreColor = Color.FromArgb((int)PInvoke.GetTextColor(nmcd->hdc).Value);
Color backColor = Color.FromArgb((int)PInvoke.GetBkColor(nmcd->hdc).Value);

However, if I interpret the documentation for the GetTextColor function correctly, it returns a COLORREF value, which only appears to be an RGB color representation with remaining byte set to 0 (0x00bbggrr). Is this the explanation why the alpha component is 0 in the ForeColor and BackColor properties?

Steps to reproduce

var listView = new ListView { OwnerDraw = true, View = View.Details, Columns = { "A", "B", "C" } };
listView.DrawColumnHeader += (s, e) => e.Graphics.DrawString(e.Header.Text, e.Font, new SolidBrush(e.ForeColor), e.Bounds.Location);

Compare with:

var listView = new ListView { OwnerDraw = false, View = View.Details, Columns = { "A", "B", "C" } };

[Zheng-Li01]

This is a regression issue, can reproduce from 8.0 to latest .NET 10.0, cannot reproduce on .NET 6.0/7.0 and .NET Framework as below screenshot.

Not repro:

Repro:

[anders9ustafsson]

Thanks @Zheng-Li01 for starting to look into this issue. In the release/7.0 branch foreColor and backColor are defined like this (see source code):

Color foreColor = Gdi32.GetTextColor(nmcd->hdc);
Color backColor = Gdi32.GetBkColor(nmcd->hdc);

[anders9ustafsson]

Using dotPeek to decompile the .NET Framework 4.8 implementation gives this source code:

Color foreColor = ColorTranslator.FromWin32(SafeNativeMethods.GetTextColor(new HandleRef(this, ptr2->hdc)));
Color backColor = ColorTranslator.FromWin32(SafeNativeMethods.GetBkColor(new HandleRef(this, ptr2->hdc)));

[JeremyKuhne]

@anders9ustafsson Thanks for the report! I've got a fix up for .NET 10. Hopefully you can work around this by changing the color in the event args to remove the transparency.

[anders9ustafsson]

Many thanks, @JeremyKuhne ! Any chance that the fix will make it into the next .NET 8 update as well?

[JeremyKuhne]

@anders9ustafsson I would have to try and get approval from servicing. If I get approval, it might not make the next update (might be the one after). Are you able to work around this?

[anders9ustafsson]

Yes, I have already implemented a workaround, so we can cope without a correction in .NET 8. I just want to get rid of the workaround as soon as possible 🙂

[Philip-Wang01]

Verified the issue on latest .NET SDK 10.0.100-preview.3.25155.12 + private dlls built from the main branch of WinForms repo. The issue has been fixed that the text can be seen in the header.