Question

I have some simple Dependency Properties that are not working. I’ve looked over them, looked over code I’ve used in the past, and I’m not sure why they are not working.

I have a custom base class (MyBaseControl) that extends UserControl, and my custom UI controls then extend on that. For example, MyCustomControl extends MyBaseControl.

MyCustomControl XAML is simple enough:

<StackPanel>
    <Image Source="{Binding Icon}" />
    <TextBlock Text="{Binding Blurb}" />
</StackPanel>

MyCustomControl Code looks like this:

public partial class MyCustomControl: MyBaseControl
{
    //public static readonly DependencyProperty IconProperty = Image.SourceProperty.AddOwner(typeof(MyCustomControl));
    //public static readonly DependencyProperty BlurbProperty = TextBlock.TextProperty.AddOwner(typeof(MyCustomControl));

    public static readonly DependencyProperty IconProperty =
        DependencyProperty.Register(
        "Icon",
        typeof(ImageSource),
        typeof(MyCustomControl),
        new PropertyMetadata(null));

    public static readonly DependencyProperty BlurbProperty =
        DependencyProperty.Register(
        "Blurb",
        typeof(String),
        typeof(MyCustomControl),
        new PropertyMetadata(null));

    public MyCustomControl() : base()
    {
        InitializeComponent();
    }

    #region Properties

    public ImageSource Icon
    {
        get { return (ImageSource)GetValue(IconProperty); }
        set { SetValue(IconProperty, value); }
    }

    public String Blurb
    {
        get { return (String)GetValue(BlurbProperty); }
        set { SetValue(BlurbProperty, value); }
    }

    #endregion Properties
}

Notice that I’ve tried a few different ways to define the DependencyProperty. Neither works.

I call my control in the following way:

<ctrl:MyCustomControl Height="240" VerticalAlignment="Center" HorizontalAlignment="Center" Width="320" Blurb="Slide Show" Icon="pack://application:,,,/Resources/photo_scenery.png" />

If I set the Source or Text directly in the XAML, they show up just fine. The bindings are just not wanting to work properly.

What am I missing that is not allowing my bindings to pass through?

Thank you for any help!

UPDATE: I’ve updated the code based on comments and additional changes I’ve tried.

Answer 1

You are registering Icon property incorrectly. In its registration method you need to specify the DP name i.e. in place of “IconProperty” it should be “Icon” –

public static readonly DependencyProperty IconProperty =
        DependencyProperty.Register(
        "Icon",
        typeof(ImageSource),
        typeof(MyCustomControl),
        new PropertyMetadata(null));

Also, try setting RelativeSource in your bindings like this –

<StackPanel>
    <Image Source="{Binding Icon, RelativeSource={RelativeSource 
            Mode=FindAncestor, AncestorType={x:Type ctrl:MyCustomControl}}}" />
    <TextBlock Text="{Binding Blurb, RelativeSource={RelativeSource 
            Mode=FindAncestor, AncestorType={x:Type ctrl:MyCustomControl}}}" />
</StackPanel>