在WPF中使用Expander创建“全部展开”和“全部折叠”按钮

<Expander Header="内容标题">
    <!-- 需要展开和折叠的内容 -->
</Expander>

<Button Content="全部展开" Click="ExpandAll_Click"/>
<Button Content="全部折叠" Click="CollapseAll_Click"/>

private void ExpandAll_Click(object sender, RoutedEventArgs e)
{
    foreach (Expander expander in FindVisualChildren<Expander>(this))
    {
        expander.IsExpanded = true;
    }
}

private void CollapseAll_Click(object sender, RoutedEventArgs e)
{
    foreach (Expander expander in FindVisualChildren<Expander>(this))
    {
        expander.IsExpanded = false;
    }
}

private static IEnumerable<T> FindVisualChildren<T>(DependencyObject dependencyObject) where T : DependencyObject
{
    if (dependencyObject != null)
    {
        for (int i = 0; i < VisualTreeHelper.GetChildrenCount(dependencyObject); i++)
        {
            DependencyObject child = VisualTreeHelper.GetChild(dependencyObject, i);
            if (child != null && child is T)
            {
                yield return (T)child;
            }

            foreach (T childOfChild in FindVisualChildren<T>(child))
            {
                yield return childOfChild;
            }
        }
    }
}