wpf设置焦点问题

发布于 2024-09-27 03:29:52 字数 450 浏览 1 评论 0原文

你好我无法将焦点集中在控制父级上。我有一个放置在画布上的控件。如果我单击该控件，我需要将焦点设置在画布上才能处理一些键盘事件。然而，尽管我试图将焦点设置为

 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。

原文

Hi
I'm not able to set focus on parent of control. I have a control which is placed on canvas.
If I click that control I need to set focus on canvas in order to handle some keyboard events.
However despite the fact that I was trying to set focus like that

 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


        }

Keyboard events which are attached to canvas don't fire.

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烟雨凡馨 2024-10-04 03:29:52

确保画布具有可聚焦和IsEnabled 均设置为 true。否则，Focus() 将失败。来自 Focus() 文档：

要获得焦点，Focusable 和 IsEnabled 都必须为 true。

此外，由于您是在 PreviewMouseDown 事件中执行此操作，因此您可能需要按如下方式重新设计您的方法：

 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);
 }

Make sure that the Canvas has Focusable and IsEnabled both set to true. Without that, Focus() will fail. From Focus() docs:

To be focusable, Focusable and IsEnabled must both be true.

In addition, since you're doing this in a PreviewMouseDown event, you may need to rework your method as follows:

 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);
 }

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