Arrow keys and changing control's focus hang the application
- by sthay
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.
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.
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.
The following are steps to reproduce the behavior I'm seeing:
Create a usercontrol and drop a FlowLayoutPanel control and set its FlowDirection = TopDown. Then add two radiobuttons to the FlowLayoutPanel.
Provide an event handler in the usercontrol
public event EventHandler CheckedChanged
{
add { radioButton2.CheckedChanged += value; }
remove { radioButton2.CheckedChanged -= value; }
}
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();
}
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.
