InputReader.KeyDown don't work

Hi, I have some code as following:

public override void CreateInput()
{
base.CreateInput();
input.KeyDown += new Axiom.KeyboardEventHandler(input_KeyDown);
}

public void input_KeyDown(object sender, Axiom.KeyEventArgs e)
{
if (e.Key == KeyCodes.C)
{
ChangeViewpoint();
}
}

But "input_KeyDown" never be handled, what's wrong about this?

Thanks in advance.

Use
public override void CreateInput()
{
base.CreateInput();
input.UseKeyboardEvents = true;
input.KeyDown += new Axiom.KeyboardEventHandler(input_KeyDown);
}

Thank you very much! I love Mogre!