Question

Whats wrong with this code. I am completely clueless.

using System;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Ink;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using System.ComponentModel;
using System.Windows.Data;

namespace CustomControls
{
    public class PercentFiller: StackPanel 
    {
        public Rectangle _FillerRectangle = null;

        public PercentFiller()
        { 
            _FillerRectangle = new Rectangle();
            _FillerRectangle.Height = this.Height;
            _FillerRectangle.Width = 20;

            _FillerRectangle.SetBinding(Rectangle.FillProperty, new Binding() {
                Source = this,
                Path = new PropertyPath("FillColorProperty"),
                Mode = BindingMode.TwoWay 
            });
            this.Background = new SolidColorBrush(Colors.LightGray); 
            this.Children.Add(_FillerRectangle);
            this.UpdateLayout();

        }

        public static readonly DependencyProperty FillColorProperty = DependencyProperty.Register(
            "FillColor",
            typeof(Brush),
            typeof(Compressor),
            new PropertyMetadata(new SolidColorBrush(Color.FromArgb(255, 134, 134, 134))));

        [Description("Gets or sets the fill color")]
        public Brush FillColor
        {
            get { return (Brush) GetValue(FillColorProperty); }
            set { SetValue (FillColorProperty, value); }
        } 
    }
}

The Rectangle Control is not getting displayed, when i add this control to another project. Please somebody help me fixing this issue.

Answer 1

You got the binding wrong (your _FillerRectangle has no DataContext).
Also, you can pass the dependency property itself to the PropertyPath.

Try changing your binding like this:

_FillerRectangle.DataContext = this; //#1: add this line
_FillerRectangle.SetBinding(Rectangle.FillProperty, new Binding()
{
    Path = new PropertyPath(FillColorProperty), // #2: no longer a string
    Mode = BindingMode.TwoWay
});

The DataContext “tells” the binding where the dependency property you’re binding is located.

Also, there’s an error in your DependencyProperty declaration:

public static readonly DependencyProperty FillColorProperty = DependencyProperty.Register(
    "FillColor",
    typeof(Brush),
    typeof(Compressor), // <- ERROR ! should be typeof(PercentFiller)
    new PropertyMetadata(new SolidColorBrush(Color.FromArgb(255, 134, 134, 134))));

The marked line should be the type of the property’s containing object, so in this case it should read typeof(PercentFiller).

UPDATE:

I forgot to add: StackPanel doesn’t have a size per-se, so:

_FillerRectangle.Height = this.Height;

Is meaningless in this context. Either set a fixed size or change your control to inherit Grid instead of StackPanel.