RelativeSource-Binding for UserControl

Question

I\'ve created a UserControl for displaying a Hyperlink in my application.

The markup of this UserControl looks like:

Answer 1

When you write

<userControls:ActionLink LinkCommand="{Binding ViewCustomersCommand}"/>

WPF tries to establish a data binding to a ViewCustomersCommand property in the DataContext of your UserControl, which is usually inherited from the control's parent, and holds a reference to some view model object. This doesn't work here because you have explicitly set the DataContext to the UserControl instance.

As soon as you have bindable properties (i.e. dependency properties) in your UserControl, you should not set its DataContext. If you do so, you will always have to specifiy the binding source objects explicitly, because the DataContext is no longer inherited.

So remove the

DataContext="{Binding RelativeSource={RelativeSource Self}}"

setting from your UserControl's XAML and set a RelativeSource in all its internal bindings:

<Hyperlink
    Command="{Binding LinkCommand,
              RelativeSource={RelativeSource AncestorType=UserControl}}"
    CommandParameter="{Binding LinkCommandParameter,
                       RelativeSource={RelativeSource AncestorType=UserControl}}">
    <TextBlock
        Text="{Binding LinkText,
               RelativeSource={RelativeSource AncestorType=UserControl}}"/>
</Hyperlink>