主题：[原创]加节点的代码的奥妙?

加根节点	Dim tr As WinForm.TreeView Dim nd As WinForm.TreeNode tr = e.Form.Controls("TreeView1") nd = tr.Nodes.Add("新节点") tr.SelectedNode = nd tr.Select() tr.BeginEdit()
增加子节点	Dim tr As WinForm.TreeView Dim nd As WinForm.TreeNode tr = e.Form.Controls("TreeView1") nd = tr.SelectedNode If nd IsNot Nothing Then     nd = nd.Nodes.Add("新节点")     tr.SelectedNode = nd     tr.Select     tr.BeginEdit End If

这二段代码不一样,但为什么一个加了根节点,一个加了子节点,看不明白.