主题：分页加载

生成目录树的代码有问题。请使用后台方式生成，如

Dim cmd As New SQLCommand
Dim dt As DataTable
cmd.CommandText = "SELECT DISTINCT 产品,客户 From {订单}"
dt = cmd.ExecuteReader()
Dim trv As WinForm.TreeView = e.Form.Controls("TreeView1")
trv.BuildTree(dt,"产品|客户")
trv.Nodes.Insert("加载所有数据",0)