Question

我尝试使用For...Next在我的数据库中保存购物车行。可以保存数据，但数据重复。

例如，我的购物车中只有两个产品，但保存了三件重复数据。

Dim x As Int16
Dim txtProductID As Label
Dim txtProductName As Label
Dim txtCategory As Label
Dim lblPrice As Label
Dim txtQuantity As TextBox
Dim lblTotalPrice As Label

For x = 0 To GridView2.Rows.Count - 1

     txtProductID = DirectCast(GridView2.Rows(x).FindControl("lblProductID"), Label)
     txtProductName = DirectCast(GridView2.Rows(x).FindControl("lblProductName"), Label)
     txtCategory = DirectCast(GridView2.Rows(x).FindControl("lblProductCategory"), Label)
     lblPrice = DirectCast(GridView2.Rows(x).FindControl("lblProductPrice"), Label)
     txtQuantity = DirectCast(GridView2.Rows(x).FindControl("txtProductQuantity"), TextBox)
     lblTotalPrice = DirectCast(GridView2.Rows(x).FindControl("lblTotalPrice"), Label)

     query &= "INSERT INTO PRODUCT2 (Prod_ID, Unit_Price, Quantity, Total_Price, Prod_Name, Prod_Category) "
     query &= "VALUES (@Prod_ID, @Unit_Price, @Quantity, @Total_Price, @Prod_Name,  @Prod_Category)"

     Using conn As New SqlConnection("Server=MEIYI-PC;Initial Catalog=VBTrading;Integrated Security=True")
         Using comm As New SqlCommand()
             With comm
                 .Connection = conn
                 .CommandType = CommandType.Text
                 .CommandText = query
                 .Parameters.AddWithValue("@Prod_ID", txtProductID.Text)
                 .Parameters.AddWithValue("@Unit_Price", txtProductName.Text)
                 .Parameters.AddWithValue("@Quantity", txtCategory.Text)
                 .Parameters.AddWithValue("@Total_Price", lblPrice.Text)
                 .Parameters.AddWithValue("@Prod_Name", txtQuantity.Text)
                 .Parameters.AddWithValue("@Prod_Category", lblTotalPrice.Text)

             End With
             Try
                 conn.Open()
                 comm.ExecuteNonQuery()
             Catch ex As Exception
                 MsgBox(ex.Message)
             End Try
         End Using
     End Using
 Next

下面是数据库和表的图像。

http://i.imgur.com/OViS8z5.jpg

Answer 1

变化：

query＆amp; =＆＃34; INSERT INTO PRODUCT2（Prod_ID，Unit_Price，Quantity，Total_Price，Prod_Name，Prod_Category）＆＃34;

要：

query =＆＃34; INSERT INTO PRODUCT2（Prod_ID，Unit_Price，Quantity，Total_Price，Prod_Name，Prod_Category）＆＃34;

没有＆amp;。

防止数据库中的重复数据

1 个答案: