在VB.NET中添加嵌套Treeview节点？

Question

我想一些项目添加到TreeView控件：

TV1.Nodes.Add("key1", "Test1") 'Works 
    TV1.Nodes("key1").Nodes.Add("key2", "Test2") 'Works (Nested) 
    TV1.Nodes("key2").Nodes.Add("key3", "Test3") 'Error (NullReferenceException) 

什么想法？谢谢:)

Answer 1

我想出了mysel F：

TV1.Nodes.Add("key1", "Test1") 
    TV1.Nodes.Find("key1", True)(0).Nodes.Add("key2", "Test2") 
    TV1.Nodes.Find("key2", True)(0).Nodes.Add("key3", "Test3") 

Answer 2

假设你想要的结构如下：

key1 
-- key2 
    -- key3 

最后一行应该是： TV1.Nodes("key1").Nodes("key2").Nodes.Add("key3", "Test3")

或用

key1 
-- key2 
-- key3 

使用TV1.Nodes("key1").Nodes.Add("key3", "Test3")

Answer 3

Public Class Test 
    Dim CurrentNode As TreeNode 

    Private Sub Search_and_Add(CurrentNode As TreeNode, NodesListArray() As String, Pointer As Integer) 
    If Pointer >= NodesListArray.Length Then 
     Exit Sub 
    End If 

    Dim BasisNodeExists As Integer = 0 
    Dim BasisNodeGID As Integer = 0 

    If Pointer = 0 Then 
     For j As Integer = 0 To TreeView1.Nodes.Count - 1 
     If TreeView1.Nodes(j).Text = NodesListArray(j) Then 
      BasisNodeExists = 1 
      BasisNodeGID = j 
     End If 
     Next 

     If BasisNodeExists = 1 Then 
     Search_and_Add(TreeView1.Nodes.Item(BasisNodeGID), NodesListArray, Pointer + 1) 
     Else 
     TreeView1.Nodes.Add(New TreeNode(NodesListArray(Pointer))) 
     Search_and_Add(TreeView1.Nodes.Item(0), NodesListArray, Pointer + 1) 
     End If 
    Else 
     Dim NewEntryRequired As Integer = 1 
     For i As Integer = 0 To CurrentNode.Nodes.Count - 1 
     If CurrentNode.Nodes.Item(i).Text = NodesListArray(Pointer) Then 
      NewEntryRequired = 0 
     End If 
     Next 
     If NewEntryRequired = 1 Then 
     CurrentNode.Nodes.Add(New TreeNode(NodesListArray(Pointer))) 
     End If 
     For i As Integer = 0 To CurrentNode.Nodes.Count - 1 
     If CurrentNode.Nodes.Item(i).Text = NodesListArray(Pointer) Then 
      Search_and_Add(CurrentNode.Nodes.Item(i), NodesListArray, Pointer + 1) 
     End If 
     Next 
    End If 
    End Sub 

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click 
    Search_and_Add(New TreeNode(), New String() {"1", "2", "3"}, 0) 
    End Sub 
End Class 

Answer 4

这里有一个简单的方法..

http://msdn.microsoft.com/en-us/library/system.windows.forms.treenode.parent.aspx

你可以把它更简单 - 只需使用IsNot运算检查，并继续前进，如果父节点存在添加。

BlueColorMan