求和特定列c#

我在这里写了这个公式，但由于某种原因，它对amt列中的所有值求和，而不是对具有itemcolumn字符串的值求和。有什么想法吗？

foreach (DataGridViewRow row in itemGrid.Rows)
{
    if (itemGrid.Rows[e.RowIndex].Cells["itemColumn"].Value.ToString() == itemcolumn)
        total += Convert.ToDecimal(row.Cells["Amt"].Value.ToString());                             
}

这是完整的代码，所以你可以看到这里发生了什么。

            private void itemGrid_CellValueChanged(object sender, DataGridViewCellEventArgs e)
            {
                //
                // [This string compares amt and amtvalue on Cell edit]
                //
                if (itemGrid.CurrentCell.ColumnIndex == 5 && isCalled)
                {
                    // Prevents loop.
                    isCalled = false;
                    decimal total = 0;
                    string itemcolumn = String.Empty;
                    {
                        foreach (DataGridViewRow row in itemGrid.Rows)
                        {
                            foreach (DataGridViewCell cell in row.Cells)
                            {
                            if (cell.Selected)
                                {
                                    itemcolumn = Convert.ToString(row.Cells["itemColumn"].Value);
                                    string strName = vendorBox.Text;
                                    string Select = "select sum(case allocated when 'Received' then amt when 'Shipped' then -amt end) as amt from lineitem WHERE item='" + itemcolumn + "';";
                                    MySql.Data.MySqlClient.MySqlConnection conDatabase = new
                                    MySqlConnection(ConnectionString.connString);
                                    MySql.Data.MySqlClient.MySqlCommand cmdDatabase = new
                                    MySql.Data.MySqlClient.MySqlCommand(Select, conDatabase);
                                    try
                                    {
                                        conDatabase.Open();
                                        MySql.Data.MySqlClient.MySqlDataReader rdrRepairOrder;
                                        rdrRepairOrder = cmdDatabase.ExecuteReader();
                                        while (rdrRepairOrder.Read())
                                        {
                                            string rowz5 = string.Format("{0}", rdrRepairOrder.GetString(0));
                                            string wut5 = rowz5.ToString();
                                            itemamt = Convert.ToInt32(wut5);
                                        }
                                        rdrRepairOrder.Close();
                                        conDatabase.Close();
                                    }
                                    catch (MySql.Data.MySqlClient.MySqlException ex)
                                    {
                                        MessageBox.Show("Error " + ex.Number + " has occurred: " + ex.Message,
                                    "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                                    }
                                }
                            }
                        }
                    }
                        // Converts amt column.
                        // amt = The cell amount.
                        // itemamt = What's on the SQL table.
                        foreach (DataGridViewRow row in itemGrid.Rows)
                        {
                          if (itemGrid.Rows[e.RowIndex].Cells["itemColumn"].Value.ToString() == itemcolumn) total += Convert.ToDecimal(row.Cells["Amt"].Value.ToString());                             
                        }
                        MessageBox.Show("Total is: " + total.ToString());
                            int amt;
                            string amtz = itemGrid.Rows[e.RowIndex].Cells["Amt"].Value.ToString();
                            amt = Convert.ToInt32(amtz);

                            int value;
                            value = itemamt - amt;
                            if (value < 0)
                            {
                                MessageBox.Show("Cannot allocate more than what it is in inventory. You have " + itemamt.ToString() + " in stock.");
                                itemGrid[5, itemGrid.CurrentCell.RowIndex].Value = itemamt;
                            }
                        }
                        isCalled = true;
                    }