On forms created with pre dotNET VB and C++ (MFC), a checkbox control responded to the plus/minus key without custom programming. When focus was on the checbox control, pressing + would check the box, no matter what the previous state (checked/unchecked), while pressing - would uncheck it, no matter the previous st开发者_如何学编程ate.
C# winform checkboxes do not seem to exhibit this behavior.
Said behavior was very, very handy for automation, whereby the automating program would set focus to a checkbox control and issue a + or - to check or uncheck it. Without this capability, that cannot be done, as the automation program (at least the one I am using) is unable to query the current state of the checkbox (so it can decide whether to issue a Space key to toggle the state to the desired one).
I've gone over the properties of a checkbox in the Visual Studio 2008 IDE and could not find anything that would restore/enable response to +/-.
Since I am in control of the sourcecode for the WinForms in question, I could replace all checkbox controls with a custom checkbox control, but blech, I'd like to avoid that - heck, I don't think I could even consider that given the amount of refactoring that would need to be done.
So the bottom line is: does anyone know of a way to get this behavior back more easily than a coding change?
I don't see an easy way to get this enabled. However, replacing the existing checkbox shouldn't be terribly daunting:
1- Create new Class Library and create new checkbox (derive from checkbox, override OnKeyPress.)
2- Reference new Library to existing projects.
3- Search and Replace System.Windows.Forms.Checkbox
with YourNamespace.NewCheckbox
As answered by Jacob G you can easily override CheckBox Control in this way:
public class MyCheckBoxOverride:CheckBox
{
protected override void OnKeyDown(KeyEventArgs e)
{
if (e.KeyCode == Keys.Oemplus)
{
this.Checked = true;
}
else if(e.KeyCode == Keys.OemMinus)
{
this.Checked = false;
}
base.OnKeyDown(e);
}
}
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