把一个Cart(维护一个DataSet)对象从第一个页面传到第二个页面,然后用DataList绑定第一个页面
private cart as new Cart
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
cart = New Cart
HttpContext.Current.Session("CART") = cart
End Sub第二个页面
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim cart As New Cart
cart = CType(HttpContext.Current.Session("CART"), BLL.Cart)
DataList1.DataSource = cart.GetCart()
DataList1.DataBind()
End Subcart对象的定义
Public Class Cart Private ds As DataSet
Private table As DataTable Public Sub New()
ds = New DataSet
table = ds.Tables.Add("cartInfo")
Dim column As DataColumn column = New DataColumn
column.ColumnName = "itemId"
column.DataType = System.Type.GetType("System.String")
table.Columns.Add(column) column = New DataColumn
column.ColumnName = "itemName"
column.DataType = System.Type.GetType("System.String")
table.Columns.Add(column) column = New DataColumn
column.ColumnName = "quantity"
column.DataType = System.Type.GetType("System.String")
table.Columns.Add(column) column = New DataColumn
column.ColumnName = "unitPrice"
column.DataType = System.Type.GetType("System.String")
table.Columns.Add(column)
End Sub Public Sub Add(ByVal itemId As String, ByVal itemName As String, ByVal quantity As String, ByVal unitPrice As String)
Dim row As DataRow = ds.Tables("cartInfo").NewRow
row("itemId") = itemId
row("itemName") = itemName
row("quantity") = quantity
row("unitPrice") = unitPrice
End Sub Public Function GetCart() As DataSet
Return ds
End Function
End Class错误:未将对象引用设置到对象实例
错在哪里了
private cart as new Cart
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
cart = New Cart
HttpContext.Current.Session("CART") = cart
End Sub第二个页面
Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim cart As New Cart
cart = CType(HttpContext.Current.Session("CART"), BLL.Cart)
DataList1.DataSource = cart.GetCart()
DataList1.DataBind()
End Subcart对象的定义
Public Class Cart Private ds As DataSet
Private table As DataTable Public Sub New()
ds = New DataSet
table = ds.Tables.Add("cartInfo")
Dim column As DataColumn column = New DataColumn
column.ColumnName = "itemId"
column.DataType = System.Type.GetType("System.String")
table.Columns.Add(column) column = New DataColumn
column.ColumnName = "itemName"
column.DataType = System.Type.GetType("System.String")
table.Columns.Add(column) column = New DataColumn
column.ColumnName = "quantity"
column.DataType = System.Type.GetType("System.String")
table.Columns.Add(column) column = New DataColumn
column.ColumnName = "unitPrice"
column.DataType = System.Type.GetType("System.String")
table.Columns.Add(column)
End Sub Public Sub Add(ByVal itemId As String, ByVal itemName As String, ByVal quantity As String, ByVal unitPrice As String)
Dim row As DataRow = ds.Tables("cartInfo").NewRow
row("itemId") = itemId
row("itemName") = itemName
row("quantity") = quantity
row("unitPrice") = unitPrice
End Sub Public Function GetCart() As DataSet
Return ds
End Function
End Class错误:未将对象引用设置到对象实例
错在哪里了
解决方案 »
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