Question

I’ve got a very simple WPF UserControl that looks like this:

namespace WpfControlLibrary1 {   public partial class UserControl1 : UserControl   {     public UserControl1()     {       InitializeComponent();       Composite = new Composite();       Composite.Color = Colors.Red;     }      protected override void OnRender(DrawingContext drawingContext)     {       Draw(drawingContext, new Rect(RenderSize));     }      public void Draw(DrawingContext g, Rect rect)     {       Composite.Draw(g, rect);     }      public Composite Composite     {       get;       set;     }   }    public class Composite   {     public void Draw(DrawingContext g, Rect rect)     {       g.DrawRectangle(new SolidColorBrush(Color), new Pen(Brushes.Black, 1.0), rect);     }      public Color Color     {       get;       set;     }   } } 

However, when I try to do this in the XAML of the Window in which the UserControl is sitting:

<Window x:Class='WpfApplication1.Window2'     xmlns='http://schemas.microsoft.com/winfx/2006/xaml/presentation'     xmlns:x='http://schemas.microsoft.com/winfx/2006/xaml'     xmlns:test='clr-namespace:WpfControlLibrary1;assembly=WpfControlLibrary1'     Title='Window2' Height='500' Width='700'>    <test:UserControl1 Name='uControl1' Composite.Color='Blue'>   </test:UserControl1> </Window> 

I get the following errors:

Error   1   The attachable property 'Color' was not found in type 'Composite'. Error   2   The property 'Composite.Color' does not exist in XML namespace 'http://schemas.microsoft.com/winfx/2006/xaml/presentation'. 

There must be simple way to get the above to work, but I’m afraid I haven’t been able to find any relevant info on the subject. Can anybody please give me a pointer or two?

Many thanks!

Answer 1

The syntax Type.Property is used to set attached properties. Try this instead:

<test:UserControl1 Name='whatever'>     <test:UserControl1.Composite>         <test:Composite Color='Blue'/>     </test:UserControl1.Composite> </test:UserControl1>