Add a new virtual property `StatusStripBorder` to `ToolStripProfessionalRenderer`

Summary

Currently, if you want to theme your application with a ToolStripProfessionalRenderer, there is an issue with the StatusStrip border, as the drawing routine uses a hardcoded value for the border color. A new virtual property should be added to the ProfessionalColorTable to customize that color. I have create a draft pull request here #4739.

Proposed API

public static class ProfessionalColors
{
        [SRDescription(nameof(SR.ProfessionalColorsSeparatorLightDescr))]
        public static Color SeparatorLight => ColorTable.SeparatorLight;

+        [SRDescription(nameof(SR.ProfessionalColorsStatusStripBorderDescr))]
+        public static Color StatusStripBorder => ColorTable.StatusStripBorder;

        [SRDescription(nameof(SR.ProfessionalColorsStatusStripGradientBeginDescr))]
        public static Color StatusStripGradientBegin => ColorTable.StatusStripGradientBegin;
}

public class ProfessionalColorTable
{
        [SRDescription(nameof(SR.ProfessionalColorsSeparatorLightDescr))]
        public virtual Color SeparatorLight => FromKnownColor(KnownColors.msocbvcrCBSplitterLineLight);

+        [SRDescription(nameof(SR.ProfessionalColorsStatusStripBorderDescr))]
+        public virtual Color StatusStripBorder => FromKnownColor(KnownColors.msocbvcrCBShadow);

        [SRDescription(nameof(SR.ProfessionalColorsStatusStripGradientBeginDescr))]
        public virtual Color StatusStripGradientBegin => FromKnownColor(KnownColors.msocbvcrCBGradMainMenuHorzBegin);
}

Implementations

public class ToolStripProfessionalRenderer : ToolStripRenderer
{
    private void RenderStatusStripBorder(ToolStripRenderEventArgs e)
    {
-        e.Graphics.DrawLine(SystemPens.ButtonHighlight, 0, 0, e.ToolStrip.Width, 0);
+        e.Graphics.DrawLine(ColorTable.StatusStripBorder, 0, 0, e.ToolStrip.Width, 0);
    }
}

Example

Create a custom color table deriving from ‘ProfessionalColorTable’ and overwrite the new virtual property ‘StatusStripBorder’ with the desired color:

public sealed class MyColorTable : ProfessionalColorTable
{
    public override Color StatusStripBorder => Color.FromArgb(50, 50, 50);
}

Create a custom renderer deriving from ‘ToolStripProfessionalRenderer’ feeding the base constructor an instance of the custom color table created earlier:

public sealed class MyRenderer : ToolStripProfessionalRenderer
{
    public MyRenderer() : base(new MyColorTable())
    {
    }
}

Now just set the created renderer to be the renderer of the ‘StatusStrip’ where desired:

StatusStrip statusStrip = new StatusStrip();
statusStrip.Renderer = new MyRenderer();

[Lydia-Shi]

Verified the issue with 6.0.100-rc.1.21424.1 build, this issue is fixed.

[merriemcgaw]

During implementation we will want to make sure that High Contrast themes are honored and we’re able to adjust when a user needs to have High Contrast. Obviously a user can override to something that doesn’t work in high contrast, but our defaults need to be accessible.

Other than validating that, I have no personal objections.