How can I determine when control key is held down during button click

Question

How can I determine when the control key is held down during button click in a C# Windows program? I want one action to take place for Ctrl/Click and a different one for Click.

Thank you

Answer 1

Assuming WinForms, use Control.ModifierKeys, eg:

private void button1_Click(object sender, EventArgs e) {
    MessageBox.Show(Control.ModifierKeys.ToString());
}

Assuming WPF, use Keyboard.Modifiers, eg:

private void Button_Click(object sender, RoutedEventArgs e) {
    MessageBox.Show(Keyboard.Modifiers.ToString());
}

Answer 2

And a little bit more:

private void button1_Click ( object sender, EventArgs e )
{           
        if( (ModifierKeys  & Keys.Control) == Keys.Control )
        {
            ControlClickMethod();    
        }
        else
        {
            ClickMethod();
        }
    }

    private void ControlClickMethod()
    {
        MessageBox.Show( "Control is pressed" );
    }

    private void ClickMethod()
    {
        MessageBox.Show ( "Control is not pressed" );
    }