WPF 自定义附加属性

public static bool GetChangedSatesProperty(DependencyObject obj)
{
return (bool)obj.GetValue(ChangedSatesProperty);
}

public static void SetChangedSatesProperty(DependencyObject obj, bool value)
{
obj.SetValue(ChangedSatesProperty, value);
}

public static readonly DependencyProperty ChangedSatesProperty =
DependencyProperty.RegisterAttached(
"ChangedSatesProperty",
typeof(bool),
typeof(StateManager),
new PropertyMetadata((dependencyObject, args) =>
{
var frameworkElement = dependencyObject as FrameworkElement;
if (frameworkElement == null && !(bool)args.NewValue)
return;
if (frameworkElement != null)
{

frameworkElement .MouseLeftButtonDown += new MouseButtonEventHandler(ChangedSates_MouseLeftButtonDown);
}
}));

static void ChangedSates_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
{
if ((sender as DependencyObject) == null||e.ClickCount!=2) return;
var ancestor = DependencyObjectExtensions.FindAncestor<Window>(sender as DependencyObject);
if (ancestor != null)
ancestor.WindowState = ancestor.WindowState == WindowState.Normal
? WindowState.Maximized
: WindowState.Normal;
}

可以在 frameworkElement .MouseLeftButtonDown += new MouseButtonEventHandler(ChangedSates_MouseLeftButtonDown);处添加任何 对frameworkElement 的操作。比如缓动动画 所有子元素 load 增加 动画。或者 unload的时候增加事件处理。在这里记录下 已被后用