Web Forms :: Always First Row Data Getting Updated In GridView Update?

cmd.CommandText = "UPDATE tbl set SET c_amt=@c_amt,c_type=@c_type,status=@check WHERE id=@id";
cmd.Parameters.Add("@id", SqlDbType.Int).Value = Convert.ToInt32(GRD.DataKeys[e.RowIndex].Value.ToString());
cmd.Parameters.Add("@c_amt", SqlDbType.VarChar).Value = GRD.Rows[0].Cells[2].Text;
cmd.Parameters.Add("@c_type", SqlDbType.VarChar).Value =GRD.Rows[0].Cells[3].Text;
bool isChecked = ((CheckBox)GRD.Rows[0].Cells[4].Controls[0]).Checked;
cmd.Parameters.Add("@check", SqlDbType.Bit).Value = isChecked;
cmd.Connection = conn;
conn.Open();
cmd.ExecuteNonQuery();
conn.Close();

i have above code whcih gives me proper id on debug but whe i update the selected row gets updated with the first row value.