Conformation Message while closing the form?

Question

How to get conformation message while closing the form???

  private void btnClose_Click(object sender, EventArgs e)

        {

            if (MessageBox.Show("Are You Sure To Close ?", "Close", MessageBoxButtons.YesNo) == DialogResult.Yes)

            {

                this.Close();

            }

           

        }

And In form properties i changed cancleButton to  btnClose...

can any one help me?????