Question

Here is my issue, I created a UserControl as follows:

XAML:

<UserControl x:Class="ProcessVisualizationBar.UserControl1"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
         mc:Ignorable="d" xmlns:lb="clr-namespace:ProcessVisualizationBar"
         Name="ProcessVisualizationBar">

    <Border BorderBrush="Silver" BorderThickness="1,1,1,1" Margin="0,5,5,5" CornerRadius="5" Padding="2">
        <ListBox Name="ProcessVisualizationRibbon" Grid.Column="1" Height="40" ItemsSource="{Binding ElementName=ProcessVisualizationBar, Path=ItemsSource}"/>
    </Border>

</UserControl>

Code Behind(C#):

using System.Windows;
using System.Windows.Controls;

namespace ProcessVisualizationBar
{
    public partial class UserControl1 : UserControl
    {
        public static readonly DependencyProperty ItemsSourceProperty = DependencyProperty.Register("ItemsSource", typeof(System.Collections.IEnumerable), typeof(UserControl));

        public System.Collections.IEnumerable ItemsSource
        {
            get { return ProcessVisualizationRibbon.ItemsSource; }
            set { ProcessVisualizationRibbon.ItemsSource = value; }
        }

        public UserControl1()
        {
            InitializeComponent();
        }
    }
}

I build my Usercontrol and add the .dll to the reference of another project. I add the reference at the top of my XAML as such:

xmlns:uc="clr-namespace:ProcessVisualizationBar;assembly=ProcessVisualizationBar"

Then I go to use the control.

<uc:UserControl1 Grid.Row="2" x:Name="ProcessVisualizationContent" />

It finds the control okay, but when I try and find the ItemsSource Property I added to it, I’m not finding it. I’m not sure what I missed, and I’m not sure what debug tools are really available to figure this out.

Anyone have some experience with this that can share their wisdom?

Answer 1

What is the actual data being passed? That is what you should be creating and not a pass through situation which you are attempting.

Create a dependency property targetting the actual data to be passed with a property changed handler. On the change event, then call internal code to bind it to the ProcessVisualazation ItemsSource. That way you can debug when the data comes through by placing a breakpoint in the event.

Here is an example where the consumer will see StringData in the Xaml and needs to pas a list of strings into the custom control:

  #region public List<string> StringData
  /// <summary>
  /// This data is to be bound to the ribbon control
  /// </summary>
  public List<string> StringData
  {
     get { return GetValue( StringDataProperty ) as List<string>; }
     set { SetValue( StringDataProperty, value ); }
  }

  /// <summary>
  /// Identifies the StringData dependency property.
  /// </summary>
  public static readonly System.Windows.DependencyProperty StringDataProperty =
      System.Windows.DependencyProperty.Register(
          "StringData",
          typeof( List<string> ),
          typeof( UserControl ),
          new System.Windows.PropertyMetadata( null, OnStringDataPropertyChanged ) );

  /// <summary>
  /// StringDataProperty property changed handler.
  /// </summary>
  /// <param name="d">DASTreeBinder that changed its StringData.</param>
  /// <param name="e">Event arguments.</param>
  private static void OnStringDataPropertyChanged( System.Windows.DependencyObject d, System.Windows.DependencyPropertyChangedEventArgs e )
  {
     UserControl source = d as UserControl;
     List<string> value = e.NewValue as List<string>;
     BindDataToRibbon( value );
  }
  #endregion public List<string> StringData 

Now just create a BindDataToRibbon method which will do the dirty work. Note that I use Jeff Wilcox’s Silverlight dependency snippets in Visual Studio to generate the above dependency. I have used it for WPF and Silverlight projects.