箭头键和更改控件的焦点将应用程序挂起 [英] Arrow keys and changing control's focus hang the application

问题描述

我有一个用户控件，其中包含一个FlowLayoutPanel(自上而下的流程)和一堆单选按钮.该控件公开一个CheckedChanged事件，该事件在单选按钮的一项检查更改时触发.

I have a usercontrol that contains a FlowLayoutPanel (topdown flow) with a bunch of radiobuttons. The control exposes a CheckedChanged event that fires whenever one of the radiobuttons's check changed.

我的表单包含用户控件和文本框.我订阅了usercontrol的CheckedChanged事件，并根据要选中的单选按钮，禁用文本框或将焦点放在文本框内.

My form contains the usercontrol and a textbox. I subscribe the usercontrol's CheckedChanged event and depending on which radiobutton gets checked, I either disable the textbox or put a focus inside the textbox.

在更改单选按钮的检查状态时，所有这些都可以通过鼠标单击正常运行.但是，使用箭头键时，它将无限期地挂起.我不明白为什么会有所不同.

All this works fine with mouseclick when changing the radiobutton's check state. However, this will hang indefinitely when using the arrow keys. I don't understand why the difference.

以下是重现我所看到的行为的步骤:

The following are steps to reproduce the behavior I'm seeing:

1. 创建一个用户控件，并放置一个FlowLayoutPanel控件并设置其FlowDirection = TopDown.然后将两个单选按钮添加到FlowLayoutPanel.

1. Create a usercontrol and drop a FlowLayoutPanel control and set its FlowDirection = TopDown. Then add two radiobuttons to the FlowLayoutPanel.

在用户控件中提供事件处理程序

Provide an event handler in the usercontrol

public event EventHandler CheckedChanged
{
    add { radioButton2.CheckedChanged += value; }
    remove { radioButton2.CheckedChanged -= value; }
}

创建一个Windows窗体并删除上面的用户控件.添加一个文本框并将Enabled设置为False.订阅用户控件的CheckedChanged事件，如下所示

Create a windows form and drop the above user control. Add a textbox and set Enabled to False. Subscribe to the usercontrol's CheckedChanged event as follows

private void userControl11_CheckedChanged(object sender, EventArgs e)
{
    textBox1.Select();
}

运行.请注意，如果使用鼠标在单选按钮之间单击，则一切正常.但是如果使用向上/向下箭头键，它将崩溃.

Run. Notice that if you use the mouse to click between the radiobuttons, thing works fine; but it will crash if you use the up/down arrow keys.

推荐答案

public event EventHandler CheckedChanged
{
    add {
         radioButton2.CheckedChanged += value;
        }
    remove {
         radioButton2.CheckedChanged -= value;
        }
}

嗯，value未初始化?还是我错过了什么?

Hmm, value is uninitialized? Or am I missing something?

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