更新表失败，没有任何错误

Question

我目前面临一个奇怪的问题，每次我想将我的表值字段从保留更新为已取消。

每当我点击按钮时它就会弹出任何错误但是当我去我的ms-access检查时它永远不会改变......

我的方法：

    public static void CancelClasses(int rid, int mid)
    {
        OleDbConnection myconnection = GetConnection();
        string mysql = "UPDATE ClassesReservation SET Status = 'cancelled' WHERE ReservationID= "+rid+" AND MID="+mid+";";
        OleDbCommand mycmd = new OleDbCommand(mysql, myconnection);
        try
        {
            myconnection.Open();
            mycmd.ExecuteNonQuery();
        }
        catch
        {
            throw;
        }
        finally
        {
            myconnection.Close();
        }
    }

按钮功能：

    protected void CancelWS_Click(object sender, EventArgs e)
    {
        if (ListBox3.SelectedIndex < 0)
        {
            Label2.Text = "Invalid Submit! Please select an Class or Workshop";
        }
        else
        {
            int reid = int.Parse(ListBox3.SelectedValue);
            int MID = Convert.ToInt32(Session["memberid"]);

            DBconn.CancelClasses(reid, MID);

        }
    }