C# KeyEventArgs has wrong KeyCode and KeyData values

Question

I registered a handler for the KeyDown event of my Windows Forms form. I want to react to pressing of Ctrl and +. Here I mean the + key which is not in the calculator part of the keyboard. While debugging I saw that if I press only this key, the KeyCode of the KeyEventArgs object is LButton | RButton | Back | ShiftKey | Space | F17. Then I tested some other keys. Also for some simple number and letter keys I get this code. Can anyone please tell me why this is the case? Furthermore I cannot understand why a click of the mouse buttons are given as Keys values. And why are they in the KeyCode if I only pressed some key? But the F17 key is still stranger. As far as I know a keyboard has only function keys from F1 to F12. What is this F17 key?

The handler is the following method:

private void MainForm_KeyDown(object sender, KeyEventArgs e)
{
    if(e.KeyCode == Keys.Escape)
    {
        Close();
        e.Handled = true;
    }
    else if((e.Modifiers==Keys.Control)&&(e.KeyCode==Keys.Add))
    {
        /* omitted */
        e.Handled = true;
    }
    else if((e.Modifiers==Keys.Control)&&(e.KeyCode == Keys.Subtract)&&(lbFiles.SelectedItems.Count>0))
    {
        /* omitted */
        e.Handled = true;
    }
}

This handler is registered by the forms designer.

Answer 1

Your answer is in the documentation for the Keys enumeration...

http://msdn.microsoft.com/en-us/library/system.windows.forms.keys%28v=vs.110%29.aspx

Do not use the values in this enumeration for combined bitwise operations. The values in the enumeration are not mutually exclusive.

KeyCode is a single value and the comparison should be equality only.