c# - 如何在WPF中设置当前窗口的所有可见和可聚焦控件的TabIndex

Question

单击按钮后，我试图遍历可视树并列出当前窗口的所有可见和可聚焦组件控件（例如按钮、图像、文本框等），并将它们的 TabIndex 设置为某个值。然而，一些控件没有被列出或者 tabIndexes 没有被设置！

这是我从这里采用的课程

 public class TabIndexer
{
    public IEnumerable<Control> FindVisualChildren(DependencyObject depObj)
    {
        if (depObj != null)
        {
            for (int i = 0; i < VisualTreeHelper.GetChildrenCount(depObj); i++)
            {
                DependencyObject child = VisualTreeHelper.GetChild(depObj, i);
                if (child != null && child is Control)
                {
                    yield return (Control)child;
                }

                foreach (var childOfChild in FindVisualChildren(child))
                {
                    yield return (Control)childOfChild;
                }
            }
        }
    }

    public T FindChild<T>(DependencyObject parent, string childName) where T : DependencyObject
    {
        // Confirm parent and childName are valid. 
        if (parent == null) return null;

        T foundChild = null;

        int childrenCount = VisualTreeHelper.GetChildrenCount(parent);
        for (int i = 0; i < childrenCount; i++)
        {
            var child = VisualTreeHelper.GetChild(parent, i);
            // If the child is not of the request child type child
            T childType = child as T;
            if (childType == null)
            {
                // recursively drill down the tree
                foundChild = FindChild<T>(child, childName);

                // If the child is found, break so we do not overwrite the found child. 
                if (foundChild != null) break;
            }
            else if (!string.IsNullOrEmpty(childName))
            {
                var frameworkElement = child as FrameworkElement;
                // If the child's name is set for search
                if (frameworkElement != null && frameworkElement.Name == childName)
                {
                    // if the child's name is of the request name
                    foundChild = (T)child;
                    break;
                }
            }
            else
            {
                // child element found.
                foundChild = (T)child;
                break;
            }
        }

        return foundChild;
    }
}

这就是它的名称

private void Button_Click(object sender, RoutedEventArgs e)
    {
        var children = new TabIndexer().FindVisualChildren(this).Where(o => o.Focusable && o.Visibility == Visibility.Visible);

        int i = 0;
        foreach (var item in children)
        {
            item.TabIndex = i;
            ++i;
        }
        MessageBox.Show("no="+i);
    }