主题：一个目录树操作实现问题

没有例子，不能测试

如下代码，试一下

’目录树的BeforeExpandNode 事件

Dim sql As String =  "Select  NodeID, NodeName ,NodeType  FROM 表名 WHERE ParentID = " & e.Node.Name
Dim cmd As new SQLCommand
cmd.ConnectionName = 数据源   ‘如果是外部表，就加上
Dim dt As DataTable
cmd.CommandText = sql
dt = cmd.ExecuteReader()
if dt Is NoThing Then Return
e.Sender.StopRedraw()
e.Node.Nodes.Clear
Dim nd As WinForm.TreeNode
For Each dr As DataRow In dt.DataRows
   nd = e.Node.Nodes.Add(dr("NodeID"),dr("NodeName"))
    If dr("NodeType") = 0 Then
        nd.Nodes.Add("")
    End If
Next
e.Sender.ResumeRedraw()

'控件窗口的AfterLoad  事件

Dim sql As String =  "Select  NodeID, NodeName  FROM 表名 WHERE ParentID = -1 "
Dim cmd As new SQLCommand
cmd.ConnectionName = 数据源   ‘如果是外部表，就加上
Dim dt As DataTable
cmd.CommandText = sql
dt = cmd.ExecuteReader()
if dt Is NoThing Then Return
Dim tv As WinForm.TreeView = e.Form.Controls("TreeView1") ‘实际的控件名
Dim nd As WinForm.TreeNode
tv.StopRedraw()
For Each dr As DataRow In dt.DataRows
   nd = tv.Nodes.Add(dr("NodeID"),dr("NodeName"))
   nd.Nodes.Add("")
Next
tv.ResumeRedraw()
tv.Select