Question

这是我背后的代码

Private Property ListEmployee As List(Of Employee)
    Get
        Return Session(Me.GetType.Name)
    End Get
    Set(ByVal value As List(Of Employee))
        Session(Me.GetType.Name) = value
    End Set
End Property
Private ReadOnly Property objEmployee As Employee
    Get
        Dim obj As New Employee
        obj.User_ID = txtUserID.Text.Trim
        obj.Name = txtName.Text.Trim
        obj.Position = txtPosition.Text.Trim
        Return obj
    End Get
End Property
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

End Sub
Protected Sub btnAddtoTable_Click(sender As Object, e As EventArgs) Handles btnAddtoTable.Click
    ListEmployee.Add(objEmployee) 'error at here
    gvResult.DataSource = ListEmployee
    gvResult.DataBind()
End Sub

结束班

我尝试将数据作为（类员工）添加到ListEmployee中（员工列表），然后在gridview上显示但是我收到了错误。

Answer 1

最好是断点并将函数拆分以查看故障所在但查看代码我很确定问题出在ListEmployee对象中。 ListEmployee.Add()将获得对ListEmplyee对象的引用，并且您不会检查此对象是否确实存在。您需要在ListEmployee属性和objEmployee中执行一些数据验证检查，我将在ListEmployee为您执行此操作：

Private Property ListEmployee As List(Of Employee)
Get
    If Not IsNothing(Session(Me.GetType.Name)) Then
       Return Session(Me.GetType.Name)
    Else
       Dim le as New List(Of Employee)
       le.add(objEmployee)
       Session(Me.GetType.Name) = le
       Return le
    End If
End Get
Set(ByVal value As List(Of Employee))
    Session(Me.GetType.Name) = value
End Set
End Property

我收到错误＆＃34;对象引用没有设置为对象的实例＆＃34;

1 个答案: