在一个c#方法中使用多个sql命令

范围:学校项目使用:VS-2010，基于服务的数据库经验水平:初学者2个月的基本编码

一般信息:{库存，销售，采购记录}windows(表单)应用系统，基于服务的数据库。

问题:在"添加订单"方法下的"客户订单信息表单"中，我想:

1. 将表单输入赋值到变量
2. 使用第一个读取器从"库存详细信息表"中读取产品数量等
3. 将数据存储在变量
中
4. 计算新库存数量和其他需求信息
5. Sql将表单输入插入到'order details table'

6. Sql将新数量更新到'Inventory details表'

     private void btnAdd_Click(object sender, EventArgs e)
   { 
       try
       {//
           //1. declare variables
           int OrderID;
           string CusName;
           string GoodsIssued = "";
           // for data entry into table
           string Entry1 = "";
           string Entry2 = "";
           string Entry3 = "";
           // for calulation of new stock level
           int ProductIDA = 0;
           int QuantityOut = 0;
           int OldQty = 0;
           int NewQty = 0;
           int ReorderLvl = 0;
           string ReorderState = "";
           //Boolean error = false;
           //2. get values from textboxes to variable
           OrderID = int.Parse(txtOrderID.Text);
           CusName = txtCustomerName.Text;
           if (rbYes.Checked == true)
           { GoodsIssued = "Yes"; }
           else if (rbNo.Checked == true)
           { GoodsIssued = "No"; }
           else { GoodsIssued = ""; } // further Error reporting possible
           /*due to complication we are compartmentalizing each iteam invoice*/
           Entry1 = txtOQty.Text + "-" + txtItemID.Text;
           Entry2 = txtOQty2.Text + "-" + txtItemID2.Text;
           Entry3 = txtOQty3.Text + "-" + txtItemID3.Text;
           //Sql instert data needs finish here
           //SQL sql Search data needs follow
           ProductIDA = int.Parse(txtItemID.Text);
           //
           //
           //
           string search = "SELECT * FROM tblInventoryDetails WHERE [Product ID] = " + ProductIDA + "";
   
           SqlCommand recall = new SqlCommand(search, con);
           con.Open();
           SqlDataReader reader = recall.ExecuteReader();
   
           while (reader.Read())// Readers need to be read using a loop!!
           {
               //string searchedId = reader[0].ToString();
               //ID  at loction 0 is ommited =can be included
               OldQty = Convert.ToInt32(reader[5]);
               ReorderLvl = Convert.ToInt32(reader[6]);
               ReorderState = reader[7].ToString();
           }
               ////////////////////////////////
           NewQty = OldQty - QuantityOut;
           if (NewQty >= ReorderLvl)   //verify syntax
           { ReorderState = "No"; }
           else { ReorderState = "Yes"; }
           con.Close();
           //3. create the query for entering new values into Order details table
           string insert = "INSERT INTO tblCustomerOrderDetails VALUES (" + OrderID + ", '" + CusName + "', '" + GoodsIssued + "', '" + Entry1 + "', '" + Entry2 + "', '" + Entry3 + "' )";
           string update = "UPDATE tblInventoryDetails SET Quantity= " + NewQty + ", [Re-Order Recommendation]='" + ReorderState + "' WHERE [Product ID] =" + ProductIDA;
           //4. Creating the sql command with query name and connection
           SqlCommand cmdInsert = new SqlCommand(insert, con);
           SqlCommand cmdUpdate = new SqlCommand(update, con);
           //5. Opening connection path
           con.Open();
           //6. Executing the command
           cmdInsert.ExecuteNonQuery();
           cmdUpdate.ExecuteNonQuery();
           //7.Display message if these try is sucessful
           MessageBox.Show("Updated and Saved Sucessfully");
       }// close of try 
       catch (Exception ex)
       {   //8. display error message when its not sucessful
           MessageBox.Show("Error while saving" + ex);
       }// close of catch
       finally
       {  //9.Close the connection
           con.Close();
       }// close of finally
       //
   }
   

这是订单详细信息表单:OrderDetails

更新问题:查询的Update部分，我希望在InventoryDetails表中更新Quantity的新值和重新订购建议，但在运行时似乎没有通过。其他一切似乎都很好。谁能指出我的错误或告诉我为什么更新功能似乎不运行?

观察:这是因为这是第二个[ExecuteNonQuery()]为这个连接?

Thanks in advance