WPF Binding to UserControl´s DependencyProperty not working as expected

Question

I have some strange problem with DependecyProperty-binding. To keep the question simpler i´ve created some dummy-control, that has the same unwanted behaviour

I have a UserControl, that has a DependencyProperty defined in code behind:

public static readonly DependencyProperty TestValueProperty = DependencyProperty.Register("TestValue", typeof(string), typeof(Test), new PropertyMetadata(default(string)));

public string TestValue
{    
     get { return (string)GetValue(TestValueProperty); }
     set { SetValue(TestValueProperty, value); }
}

This property is used in XAML:

<Label Content="{Binding TestValue}" />

This control should be used in another control like this:

<views:Test TestValue="{Binding Settings.Setting123}" />

Settings is defined in viewmodel as property.

But the content of Settings.Setting123 is not visible in my usercontrol´s label.

When writing some fixes value instead of the binding it works fine:

<views:Test TestValue="Test" />

But of course i do not want a fixed value, but the content of the bound object. Any hint what is going wrong here?

Thanks in advance!

Answer 1

You didn't share enough code for anybody to recreate the issue, but reading between the lines, I'm guessing that Label is in your UserControl XAML. If TestValue is a property of your UserControl, this will probably work:

<Label Content="{Binding TestValue, RelativeSource={RelativeSource AncestorType=UserControl}}" />

One thing you did right: Your UserControl constructor must always set DataContext = this;. No exceptions.