Dependency properties and standard properties are quite different. The key features delivered by dependency properties are support for binding and animation. If you want to assign a value to a property using a Binding or template binding that property needs to be a dependency property. When animating a property the a dependency property can track … Read more
The correct way to override a base class’s property is: static TestControl() { FooProperty.OverrideMetadata( typeof(TestControl), new FrameworkPropertyMetadata(67) ); } EDIT: AddOwner is meant to share the same DependencyProperty across types that are not related (i.e. the TextProperty of TextBox and TextBlock).
It’s easy, actually (via RegisterReadOnly): public class OwnerClass : DependencyObject // or DependencyObject inheritor { private static readonly DependencyPropertyKey ReadOnlyPropPropertyKey = DependencyProperty.RegisterReadOnly( nameof(ReadOnlyProp), typeof(int), typeof(OwnerClass), new FrameworkPropertyMetadata(default(int), FrameworkPropertyMetadataOptions.None)); public static readonly DependencyProperty ReadOnlyPropProperty = ReadOnlyPropPropertyKey.DependencyProperty; public int ReadOnlyProp { get { return (int)GetValue(ReadOnlyPropProperty); } protected set { SetValue(ReadOnlyPropPropertyKey, value); } } //your other code here … Read more
If you want to do it in XAML, you could try using styles to achieve that. Here’s an example: <UserControl x:Class=”MyModule.MyView” xmlns:local=”clr-namespace:MyModule”> <UserControl.Resources> <Style TargetType=”local:MyView”> <Setter Property=”MyViewProperty” Value=”{Binding MyViewModelProperty, Mode=TwoWay}”/> </Style> </UserControl.Resources> <!– content –> </UserControl> In your case both MyViewProperty and MyViewModelProperty would be named MyProperty but I used different names just to be … Read more
The WPF binding engine calls GetValue and SetValue directly (bypassing the property setters and getters). You need the property to be there so it can be supported in the XAML markup (and compile correctly).
Attached properties are a type of dependency property. The difference is in how they’re used. With an attached property, the property is defined on a class that isn’t the same class for which it’s being used. This is usually used for layout. Good examples are Panel.ZIndex or Grid.Row – you apply this to a control … Read more
The “CLR-wrappers” for dependency properties only get called when done through code. XAML depends on the name specified in the DependencyProperty.Register(…) call. So, instead of “extending” the logic of the setter for your dependency property like you did above, just put your custom logic in a PropertyChangedCallback function.
The MSDN link you provided says it quite well: This method is used by a component that programmatically sets the value of one of its own properties without disabling an application’s declared use of the property. The SetCurrentValue method changes the effective value of the property, but existing triggers, data bindings, and styles will continue … Read more
The only explanation I found helpful and well written is this one: http://www.wpftutorial.net/dependencyproperties.html Basically, DependencyProperties differ from regular properties in that they’re not just setters / getters for fields in the class, but they retrieve their actual values dynamically during runtime. The SetValue() method of DPs is pretty straightforward and sets the local value of … Read more
That is one of the many reasons you should never set the DataContext directly from the UserControl itself. When you do so, you can no longer use any other DataContext with it because the UserControl’s DataContext is hardcoded to an instance that only the UserControl has access to, which kind of defeats one of WPF’s … Read more