我有一个将项目添加到我的数组列表的函数。我的问题是它一次只能保存一个项目,因为每次单击按钮时它都会重新初始化点亮的数组。VB 中的语法是什么,仅在尚未创建数组时才对其进行初始化?
Dim itemSelectAs New ArrayList()
Dim Quantities As New ArrayList()
Dim itemQtyOrdered As Integer
Public Sub ShtickDataList_ItemCommand(ByVal source As Object, ByVal e As System.Web.UI.WebControls.ListViewCommandEventArgs) Handles ShtickDataList.ItemCommand
If e.CommandName = "addToCart" Then
Dim itemQuantity As DropDownList = e.Item.FindControl("QuantityDropDown")
itemQtyOrdered = itemQuantity.SelectedValue
ItemSelect.Add(e.CommandArgument)
Quantities.Add(itemQtyOrdered)
Session("itemInCart") = ItemSelect
Session("quantities") = Quantities
viewInvoice()
End If
End Sub
Protected Sub viewInvoice()
Dim itemSelected As ArrayList = DirectCast(Session("itemInCart"), ArrayList)
Dim QuantityofItem As ArrayList = DirectCast(Session("quantities"), ArrayList)
Dim conn As SqlConnection
Dim comm As SqlCommand
Dim reader As SqlDataReader
Dim purimConnection2 As String = ConfigurationManager.ConnectionStrings("Purim").ConnectionString
conn = New SqlConnection(purimConnection2)
comm = New SqlCommand("SELECT ProductName FROM Products WHERE ProductID = @ProductID", conn)
Dim i As Integer
For i = 0 To ItemSelect.Count - 1
comm.Parameters.Add("@ProductID", Data.SqlDbType.Int)
comm.Parameters("@ProductID").Value = (ItemSelected.Count - 1)
'Next
Try
conn.Open()
reader = comm.ExecuteReader()
ViewCartlink.Text = "View Cart: (" & ItemSelected.Count & ")"
Finally
conn.Close()
End Try
End Sub