主题：加载树显示统计数据

Dim cmd As New SQLCommand
Dim dt As DataTable
cmd.CommandText = "SELECT 产品,客户,雇员, Count([_Identify]) As 订单数 From {订单} Group By 产品,客户,雇员"
dt = cmd.ExecuteReader()
Dim trv As WinForm.TreeView = e.Form.Controls("TreeView1")
trv.BuildTree(dt, "产品|客户|雇员")
trv.StopRedraw
For Each nd As WinForm.TreeNode In trv.AllNodes
    Dim Value()As String
    Dim Filter As String

    Value = nd.FullName.Split("\") '注意这里用FullName属性,不能用FullPath属性
    Select Case nd.Level
        Case 0
            nd.text = nd.text & "产品"
            Filter = "产品 = " & value(0)
        Case 1
            nd.text = nd.text & "客户"
            Filter = "产品 = " & value(0) & " And 客户 = " & value(1)
        Case 2
            Filter = "产品 = " & value(0) & " And 客户 = " & value(1) & " And 雇员 = '" & Value(2) & "'"
    End Select
    nd.Text = nd.text & "(" & dt.Compute("Sum(订单数)",Filter) & "条)"
Next
trv.Nodes.Insert("加载所有行","加载所有行(" & dt.Compute("Sum(订单数)") & "条)",0)
trv.ResumeRedraw

怎么不能实现?请指教