我正在尝试使用ViewModel上的属性来动态隐藏Expander中的Toggle Button,并将其设置为Visibility属性。至少这是我的想法。是否有一种方法可以仅更改ToggleButton控件上的一个设置,而不必在xaml中执行整个ToggleButton模板?
Expander
的Loaded
事件,并在事件处理程序中设置Binding
,或者如果你想要一个可重用的方式而不需要代码后台,则可以使用附加行为。
附加行为查找Template
内部的ToggleButton
并设置Binding
到附加属性ToggleButtonVisibility
。
这里上传了一个示例应用程序:ExpanderToggleButtonVisibilityTest.zip
像这样使用:
<Expander Name="expander"
behaviors:ExpanderBehavior.BindToggleButtonVisibility="True"
behaviors:ExpanderBehavior.ToggleButtonVisibility="{Binding YourVisibilityProperty}"
.../>
ExpanderBehavior
public class ExpanderBehavior
{
public static DependencyProperty BindToggleButtonVisibilityProperty =
DependencyProperty.RegisterAttached("BindToggleButtonVisibility",
typeof(bool),
typeof(ExpanderBehavior),
new PropertyMetadata(false, OnBindToggleButtonVisibilityChanged));
public static bool GetBindToggleButtonVisibility(Expander expander)
{
return (bool)expander.GetValue(BindToggleButtonVisibilityProperty);
}
public static void SetBindToggleButtonVisibility(Expander expander, bool value)
{
expander.SetValue(BindToggleButtonVisibilityProperty, value);
}
private static void OnBindToggleButtonVisibilityChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
{
Expander expander = target as Expander;
if (expander.IsLoaded == true)
{
BindToggleButtonVisibility(expander);
}
else
{
RoutedEventHandler loadedEventHandler = null;
loadedEventHandler = new RoutedEventHandler(delegate
{
BindToggleButtonVisibility(expander);
expander.Loaded -= loadedEventHandler;
});
expander.Loaded += loadedEventHandler;
}
}
private static void BindToggleButtonVisibility(Expander expander)
{
ToggleButton headerSite = expander.Template.FindName("HeaderSite", expander) as ToggleButton;
if (headerSite != null)
{
Binding visibilityBinding = new Binding
{
Source = expander,
Path = new PropertyPath(ToggleButtonVisibilityProperty)
};
headerSite.SetBinding(ToggleButton.VisibilityProperty, visibilityBinding);
}
}
#region ToggleButtonVisibilityProperty
public static DependencyProperty ToggleButtonVisibilityProperty =
DependencyProperty.RegisterAttached("ToggleButtonVisibility",
typeof(Visibility),
typeof(ExpanderBehavior),
new PropertyMetadata(Visibility.Visible));
public static Visibility GetToggleButtonVisibility(Expander expander)
{
return (Visibility)expander.GetValue(ToggleButtonVisibilityProperty);
}
public static void SetToggleButtonVisibility(Expander expander, Visibility value)
{
expander.SetValue(ToggleButtonVisibilityProperty, value);
}
#endregion // ToggleButtonVisibilityProperty
}