原：TreeView节点自由拖动

Public   Class Form1 Class Form1
    Private Sub Form1_Load()Sub Form1_Load(ByVal sender As System.Object, _
                            ByVal e As System.EventArgs) Handles MyBase.Load
        Dim ParentNode1 As TreeNode
        Dim ParentNode2 As TreeNode
        ParentNode1 = TreeView1.Nodes.Add("tv1")
        With ParentNode1
            .Nodes.Add("tv1FirstChild")
            .Nodes.Add("tv1SecondChild")
            .Nodes.Add("tv1ThirdChild")
            .Nodes.Add("tv1FourthChild")
            .Expand()
        End With
        ParentNode2 = TreeView1.Nodes.Add("tv2")
        With ParentNode2
            .Nodes.Add("tv2FirstChild")
            .Nodes.Add("tv2SecondChild")
            .Expand()
        End With
    End Sub
    Public Sub TreeView_ItemDrag()Sub TreeView_ItemDrag(ByVal sender As Object, _
                                   ByVal e As ItemDragEventArgs) _
                                   Handles TreeView1.ItemDrag
        DoDragDrop(e.Item, DragDropEffects.Move)
    End Sub
    Public Sub TreeView_DragEnter()Sub TreeView_DragEnter(ByVal sender As Object, _
                                  ByVal e As DragEventArgs) _
                                  Handles TreeView1.DragEnter
        e.Effect = DragDropEffects.Move
    End Sub
    Public Sub TreeView_DragDrop()Sub TreeView_DragDrop(ByVal sender As Object, _
                                  ByVal e As DragEventArgs) _
                                  Handles TreeView1.DragDrop
        Dim NewNode As TreeNode
        Dim DestinationNode As TreeNode

        If e.Data.GetDataPresent("System.Windows.Forms.TreeNode", False) Then
            Dim pt As Point
            pt = CType(sender, TreeView).PointToClient(New Point(e.X, e.Y))

            DestinationNode = CType(sender, TreeView).GetNodeAt(pt)
            NewNode = CType(e.Data.GetData("System.Windows.Forms.TreeNode"), _
                                            TreeNode)

            If DestinationNode.Nodes.Count > 0 Then   '目标是目录
                DestinationNode.Nodes.Add(NewNode.Clone)
                DestinationNode.Expand()
                NewNode.Remove()
            Else  '目标不是目录
                If DestinationNode.Parent Is NewNode.Parent Then  '同级
                    If DestinationNode.Index < NewNode.Index Then
                        DestinationNode.Parent.Nodes.Insert(DestinationNode.Index, NewNode.Clone)
                        NewNode.Remove()
                    Else
                        DestinationNode.Parent.Nodes.Insert(DestinationNode.Index + 1, NewNode.Clone)
                        NewNode.Remove()
                    End If
                ElseIf Not DestinationNode.Parent Is Nothing Then 'Or NewNode.Parent.Parent Is DestinationNode.Parent Then
                    DestinationNode.Parent.Nodes.Insert(DestinationNode.Index, NewNode.Clone)
                    NewNode.Remove()
                End If
            End If
        End If
    End Sub

End Class