Question

您好我无法将注意力集中在控制之父上。我有一个放在画布上的控件。如果我单击该控件，我需要在画布上设置焦点以处理一些键盘事件。尽管事实上我试图像那样设置焦点

 protected override void OnPreviewMouseDown(MouseButtonEventArgs e)
        {
            base.OnPreviewMouseDown(e);
           Canvas designer = VisualTreeHelper.GetParent(this) as Canvas;
          designer.Focus() ;//this doesn't work
           Keyboard.Focus(designer); //this also doesn't work


        }

附加到画布的键盘事件不会触发。

Answer 1

确保Canvas的Focusable和IsEnabled都设置为true。没有它，Focus()将失败。来自Focus() docs：

要成为焦点，Focusable和IsEnabled必须都是真的。

此外，由于您在PreviewMouseDown事件中执行此操作，因此您可能需要按如下方式重新编写方法：

 protected override void OnPreviewMouseDown(MouseButtonEventArgs e)
 {
     Canvas designer = VisualTreeHelper.GetParent(this) as Canvas;
     designer.Focus() ;//this doesn't work
     Keyboard.Focus(designer); //this also doesn't work

     // Just in case something else is changing your focus as a result of a mouse event...
     e.Handled = true;
     base.OnPreviewMouseDown(e);
 }

Answer 2

使用FocusManager将画布设置为焦点范围。这里有一个很好的例子：Can't set focus to a child of UserControl。

Answer 3

I use My UserControl with attribute: Background="Transparent".

wpf设置焦点的问题

3 个答案: