通过绑定隐藏 WPF 扩展器上的切换按钮

本文关键字：按钮 扩展器 绑定 隐藏 WPF | 更新日期: 2023-09-27 18:36:46

我正在尝试使用视图模型上设置为可见性属性的属性动态隐藏扩展器上的切换按钮。至少我是这么想的。有没有办法只更改 ToggleButton 控件上的一个设置，而不必在我的 xaml 中执行切换按钮的整个模板？

通过绑定隐藏 WPF 扩展器上的切换按钮

您可以将 Loaded 事件用于Expander并在事件处理程序中设置Binding，或者如果您想要一种没有代码的可重用方式，则可以使用附加的行为。

附加行为在Template内查找ToggleButton，并设置附加到属性ToggleButtonVisibility Binding。

在此处上传了一个示例应用程序：ExpanderToggleButtonVisibilityTest.zip

像这样使用它

<Expander Name="expander"
          behaviors:ExpanderBehavior.BindToggleButtonVisibility="True"
          behaviors:ExpanderBehavior.ToggleButtonVisibility="{Binding YourVisibilityProperty}"
          .../>

扩展器行为

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
}
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