Call a function/method while pressing tab key .

public void geterpdata()
       {
           cmbbox2.Items.Clear();
           con.Open();
           string sqlqrygetdata = "select * from erpdata";
           SqlCommand sqlcmd = new SqlCommand(sqlqrygetdata, con);
           sqlcmd.ExecuteNonQuery();
           DataTable dt = new DataTable();
           SqlDataAdapter da = new SqlDataAdapter(sqlcmd);
           da.Fill(dt);
           foreach(DataRow dr in dt.Rows)
           {
               cmbbox2.Items.Add(dr["empno"].ToString());
           }
           con.Close();
       }

Public Void cmbbox1_TabIndexChanged(object sender, EventArgs e)
{

geterpdata();I want to call this function when tab key is pressing.
cmbbox2.focus();

}