when writing value in first cell of datagridview win form it give error index was out of range Must be non-negative and less than the size of the collection

Problem

I have datagridview have cell 0 is MembershipNo when write any value on datagridview give me error 

index was out of range  Must be non-negative and less than the size of the collection why and how to solve that .

Exception error happen on cell click event of datagridview on function UpdateMemberCode

  private void gridClassPlayers_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            if (gridClassPlayers.CurrentRow != null)
            {
                         UpdateMemberCode(gridClassPlayers.SelectedCells[0].Value.ToString());
            }
        }

 private void UpdateMemberCode(string MemberCodeVal)
        {

            string sql = " Update ClubTransactionType SET MemberCode =" + MemberCodeVal + "  WHERE TrxTypeID =" + GetTransaction + " AND LineNumber=1";
            DataAccess.ExecuteNonQuery(sql);

        }