WPF Custom Color MarkupExtension cannot be applied on SolidColorBrush.Color

Question

I am trying to implement a MarkupExtension to convert rgba int value to System.Windows.Media.Color.

But I am getting an exception of

An object of the type "UIH:Color" cannot be applied to a property that expects the type "System.Windows.Media.Color"

Here is the implementation:

[MarkupExtensionReturnType(typeof(System.Windows.Media.Color))]
public class Color : MarkupExtension
{
    public static explicit operator System.Windows.Media.Color(Color color)
    {
        return color.ToColor();
    }

    public byte R { get; set; }

    public byte G { get; set; }

    public byte B { get; set; }

    public byte? A { get; set; }

    public System.Windows.Media.Color ToColor()
    {
        if (A.HasValue)
        {
            return System.Windows.Media.Color.FromArgb(A.Value, R, G, B);
        }
        else
        {
            return System.Windows.Media.Color.FromRgb(R, G, B);
        }
    }

    public override object ProvideValue(IServiceProvider serviceProvider)
    {
        return ToColor();
    }
}

And I apply the color to a solidcolorbrush

<uih:Color x:Key="background" R="79" G="113" B="133" />

<SolidColorBrush x:Key="backgroundBrush" Color="{StaticResource background}" options:Freeze="True" />

Answer 1

The problem is that you are just using the wrong syntax. It is not a static resource what you need, but the markup extension syntax:

<SolidColorBrush x:Key="backgroundBrush" Color="{uih:Color R=79, G=113 ,B=133}" />

That should do the trick ;)

EDIT

If you want to reuse the Color then, as @Clemens pointed out, you do not need a markup extension or the new class at all, just declare a Color resource:

<Color x:Key="Color" R="79" G="113" B="133"/>
<SolidColorBrush x:Key="backgroundBrush" Color="{StaticResource Color}" />