Question

For example:

public class DesignerPatternBrush : Brush
{
    public string Name { get; set; }
}

I would like to define my own Brush class by adding a new property called Name, but there is a compiler error:

error CS0534: ‘Brushes.DesignerPatternBrush’ does not implement inherited abstract member ‘System.Windows.Freezable.CreateInstanceCore()’

How can I add a Name property to a Brush type?

Note this related question: How do I implement a custom Brush in WPF? It answers the question of why it is not possible to literally inherit Brush. But is there some other way (e.g. using an attached property) to achieve the same effect I want?

Answer 1

As the compile error message says is Brush an abstract class –> you have to implement its abstract members

to let Visual Studio do all the work for you there exist a shortcut.

Select the Brush class and press Alt + Shift + F10 –> Enter
the abstract class gets automatically implemented:

public class T : Brush
{

    protected override Freezable CreateInstanceCore()
    {
        throw new NotImplementedException();
    }
}

EDIT:

but this will not work with the Brush class. Visual Studio auto-implements all methods which are visible, but the Brush class defines some methods as internal abstract

i.e:

internal abstract int GetChannelCountCore();

As the Brush is defined in PresentationCore we will never be able to override the abstract method outside the assembly… –> impossible to inherit from the class