使用DataGrid上的更新/删除命令更新会话arraylist

Question

我正在创建一个购物车ArrayList，它通过数据网格显示。 我已经坚持了很长时间，无法找到一种在没有SQL的情况下无法解决数据库问题的解决方案。 会话对象包含的数据超过了在数据网格中需要显示的数据，我仅将视图限制为基本要素。

我已经包含了所有用于创建和更新的方法。

// Method to create data table and insert onto page
Public Sub createShoppingCartTable()

    Dim tableColumnCode As System.Data.DataColumn = New System.Data.DataColumn
    With tableColumnCode
        .DataType = System.Type.GetType("System.String")
        .ColumnName = "ProductCode"
        .DefaultValue = "0"
    End With
    ShoppingCartTable.Columns.Add(tableColumnCode)

    Dim tableColumnName As System.Data.DataColumn = New System.Data.DataColumn
    With tableColumnName
        .DataType = System.Type.GetType("System.String")
        .ColumnName = "Name"
        .DefaultValue = "unknown"
    End With
    ShoppingCartTable.Columns.Add(tableColumnName)

    Dim tableColumnQuantity As System.Data.DataColumn = New System.Data.DataColumn
    With tableColumnQuantity
        .DataType = System.Type.GetType("System.Int32")
        .ColumnName = "Quantity"
        .DefaultValue = "5"
    End With
    ShoppingCartTable.Columns.Add(tableColumnQuantity)

    Dim tableColumnPrice As System.Data.DataColumn = New System.Data.DataColumn
    With tableColumnPrice
        .DataType = System.Type.GetType("System.Decimal")
        .ColumnName = "Price"
        .DefaultValue = "0"
    End With
    ShoppingCartTable.Columns.Add(tableColumnPrice)

    Dim tableColumnTotalPrice As System.Data.DataColumn = New System.Data.DataColumn
    With tableColumnTotalPrice
        .DataType = System.Type.GetType("System.Decimal")
        .ColumnName = "TotalPrice"
        .DefaultValue = "0"
    End With
    ShoppingCartTable.Columns.Add(tableColumnTotalPrice)


    //create rows with products added to cart
    Dim localShoppingCart As ArrayList = Session("shoppingCartSession")
    If Not localShoppingCart Is Nothing Then
        Dim tableRow As System.Data.DataRow = ShoppingCartTable.NewRow()
        Dim intMaxRows As Integer = localShoppingCart.Count - 1
        Dim i As Integer
        Dim localObj As New Product()

        For i = 0 To intMaxRows
            localObj = localShoppingCart(i)
            tableRow = ShoppingCartTable.NewRow()
            tableRow("ProductCode") = localObj.itemID
            tableRow("Name") = localObj.itemName
            tableRow("Quantity") = localObj.itemQuantity
            tableRow("Price") = localObj.itemPrice
            tableRow("TotalPrice") = localObj.itemQuantity * localObj.itemPrice
            ShoppingCartTable.Rows.Add(tableRow)
        Next
        btnCheckout.Visible = True
        btnContinueShopping.Visible = True

    Else
        btnCheckout.Visible = False
        btnContinueShopping.Visible = False
    End If

    Me.dgDatagrid.DataSource = Me.ShoppingCartTable
    Me.dgDatagrid.DataBind()
End Sub


Private Sub refreshShoppingCart(ByVal selectedIndex As Integer)
    createShoppingCartTable()
    With dgDatagrid
        .DataSource = Me.ShoppingCartTable  
        .EditItemIndex = selectedIndex
        .DataBind()
    End With
End Sub


Private Sub dgDatagrid_EditCommand(source As Object, e As DataGridCommandEventArgs) Handles dgDatagrid.EditCommand
    refreshShoppingCart(e.Item.ItemIndex)
End Sub


Private Sub dgDatagrid_CancelCommand(source As Object, e As DataGridCommandEventArgs) Handles dgDatagrid.CancelCommand
    refreshShoppingCart(-1)
End Sub


Private Sub dgDatagrid_UpdateCommand(source As Object, e As DataGridCommandEventArgs) Handles dgDatagrid.UpdateCommand
    Dim primaryKey = CType(e.Item.Cells(3).Controls(0), TextBox).Text
    Dim number As Integer = CType(e.Item.Cells(4).Controls(0), TextBox).Text
    refreshShoppingCart(-1)
End Sub