主题：[求助]加载树报错

NodeMouseClick:

Dim Filter As String

 Dim dr As DataRow = e.Node.DataRow 

Dim Year As Integer = dr("年")

Dim Month As Integer = dr("月")

Dim day As Integer  = dr("日")

If e.node.Text = "加载所有数据" Then

    Filter = ""

Else

    Select Case e.Node.Level

        Case 0

            Filter ="Year(日期) = " & Year

        Case 1

            Filter ="Year(日期) = " & Year & " And Month(日期) = " & Month

        Case 2

            Filter ="Year(日期) = " & Year & " And Month(日期) = " & Month & " And day(日期) = " & day

    End Select

End If

DataTables("订单组合1").LoadFilter = Filter

DataTables("订单组合1").Load()

在点击加载所有数据时报错

报错信息为：未将对象引用设置到对象的实例。