WPF自定义依赖项属性

WPF自定义Usercontrol, 需要在xaml里绑定数据,  DependencyProperty是必须的.

所以定义 DependencyProperty 大概是这样

 

public UIElement FrontContent
        {
            get { return (UIElement)GetValue(FrontContentProperty); }
            set { SetValue(FrontContentProperty, value); }
        }

public static readonly DependencyProperty FrontContentProperty
            = DependencyProperty.Register(
                                        "FrontContent",
                                        typeof(UIElement),
                                        typeof(myUserControl),
                                        new PropertyMetadata(
                                                null,
                                                new PropertyChangedCallback(FrontContentChangedCallback))
                            );


private static void FrontContentChangedCallback(DependencyObject o, DependencyPropertyChangedEventArgs e)
        {
            myUserControl target = o as myUserControl;
            target.FrontContentBorder.Child = (UIElement)e.NewValue;
            target.OnFrontContentChanged(new RoutedPropertyChangedEventArgs<UIElement>(
                      (UIElement)e.OldValue, (UIElement)e.NewValue)
                                         );
        }

 

然而根据WPF规范,依赖项属性同时又是附加属性(AttachedProperty) , 现在让属性更符合规范一些

所以上面的代码就改为

 

public static readonly DependencyProperty FrontContentProperty
            = DependencyProperty.RegisterAttached(
                                        "FrontContent",
                                        typeof(UIElement),
                                        typeof(myUserControl),
                                        new PropertyMetadata(
                                                null,
                                                new PropertyChangedCallback(FrontContentChangedCallback))
                            );

//xaml内引用名为 "XXXX"
//则依赖项属性名必须为 XXXXProperty
//且必须有2个静态方法SetXXXX()和GetXXXX()

public static void SetFrontContent(myUserControltarget, UIElement value)
        {
            target.SetValue(FrontContentProperty, value);
        }

public static UIElement GetFrontContent(myUserControltarget)
        {
            return (UIElement)target.GetValue(FrontContentProperty);
        }