Como: Implement a Dependency Property
Este exemplo mostra como fazer uma common language runtime (CLR) propriedade com um DependencyProperty campo, definindo, portanto, um propriedade de dependência. Quando você definir suas próprias propriedades e deseja que eles suportam muitos aspectos do Windows Presentation Foundation (WPF) a funcionalidade, inclusive estilos, ligação de dados, herança, animação e valores padrão, você deve implementá-los como um propriedade de dependência.
Exemplo
The following example first registers a dependency property by calling the Register method. The name of the identifier field that you use to store the name and characteristics of the dependency property must be the Name you chose for the dependency property as part of the Register call, appended by the literal string Property. For instance, if you register a dependency property with a Name of Location, then the identifier field that you define for the dependency property must be named LocationProperty.
In this example, the name of the dependency property and its CLR accessor is State; the identifier field is StateProperty; the type of the property is Boolean; and the type that registers the dependency property is MyStateControl.
If you fail to follow this naming pattern, designers might not report your property correctly, and certain aspects of property system style application might not behave as expected.
You can also specify default metadata for a dependency property. This example registers the default value of the State dependency property to be false.
Public Class MyStateControl
Inherits ButtonBase
Public Sub New()
MyBase.New()
End Sub
Public Property State() As Boolean
Get
Return CType(Me.GetValue(StateProperty), Boolean)
End Get
Set(ByVal value As Boolean)
Me.SetValue(StateProperty, value)
End Set
End Property
Public Shared ReadOnly StateProperty As DependencyProperty = DependencyProperty.Register("State", GetType(Boolean), GetType(MyStateControl),New PropertyMetadata(False))
End Class
public class MyStateControl : ButtonBase
{
public MyStateControl() : base() { }
public Boolean State
{
get { return (Boolean)this.GetValue(StateProperty); }
set { this.SetValue(StateProperty, value); }
}
public static readonly DependencyProperty StateProperty = DependencyProperty.Register(
"State", typeof(Boolean), typeof(MyStateControl),new PropertyMetadata(false));
}
For more information about how and why to implement a dependency property, as opposed to just backing a CLR property with a private field, see Visão geral sobre propriedades de dependência.
Consulte também
Conceitos
Visão geral sobre propriedades de dependência