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 Cli

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());
}