Remove Empy Tree from TreeNode

Question

i have treenode that look like next text: 

*1
 **Ron
 **Dani
 **Mary
 **John
*2
*3
 **Sammit
 **Ram
*4
*6
 **Orit
 **Sami
 **Mor
*7
*8
*9
*10

i want to remove all  empty root nods ("2","4","7","8","9","10) and keep root with nods (in this case: "1","3,"6")

so i created loop for it:

  Public Sub RemoveMainEmptyNods()

        For Each Nod As TreeNode In TreeNode1.Nodes
            If Nod.Nodes.Count = 0 Then
                Nod.Remove()
            End If
        Next


    End Sub

for some reason, is not remove all empty root nodes. every time is keep the root "8", so this is the results that i get:

*1
 **Ron
 **Dani
 **Mary
 **John
*3
 **Sammit
 **Ram
*6
 **Orit
 **Sami
 **Mor
*8

when i run the loop again, i get the right result(see blow):

*1
 **Ron
 **Dani
 **Mary
 **John
*3
 **Sammit
 **Ram
*6
 **Orit
 **Sami
 **Mor

so why is not work on the first time?

Answer 1

In the following treenode1 is a treeview.

        Dim n As TreeNode = treenode1.Nodes(0).FirstNode

        Do While Not IsNothing(n)
            If n.Nodes.Count = 0 Then
                Dim nn As TreeNode = n.NextNode
                n.Remove()
                n = nn
            Else
                n = n.NextNode
            End If
        Loop

---

'Those who use Application.DoEvents() have no idea what it does and those who know what it does never use it.'  JohnWein

Multics

My Serial Port Answer

Answer 2

The problem is when you remove a node the position of nod changes. If you step through your code one line at a time and look at the values of nod you will see.

One solution is to jump out of the for and start the count again like this. I am sure there are better ways.

Public Class Form2
    Private Sub Form2_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim NewNode As TreeNode
        Dim ChildNode As TreeNode

        With TreeView1
            NewNode = .Nodes.Add("1")
            ChildNode = NewNode.Nodes.Add("Ron")
            ChildNode = NewNode.Nodes.Add("Dani")
            ChildNode = NewNode.Nodes.Add("Mary")
            ChildNode = NewNode.Nodes.Add("John")
            NewNode = .Nodes.Add("2")
            NewNode = .Nodes.Add("3")
            ChildNode = NewNode.Nodes.Add("Sammit")
            ChildNode = NewNode.Nodes.Add("Ram")
            NewNode = .Nodes.Add("4")
            NewNode = .Nodes.Add("6")
            ChildNode = NewNode.Nodes.Add("Orit")
            ChildNode = NewNode.Nodes.Add("Sami")
            ChildNode = NewNode.Nodes.Add("Mor")
            NewNode = .Nodes.Add("7")
            NewNode = .Nodes.Add("8")
            NewNode = .Nodes.Add("9")
            NewNode = .Nodes.Add("10")

        End With
    End Sub

    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        Dim exitflag As Boolean = True
        Do While exitflag
            exitflag = False
            For Each Nod As TreeNode In TreeView1.Nodes
                If Nod.Nodes.Count = 0 Then
                    Nod.Remove()
                    exitflag = True
                    Exit For
                End If
            Next
        Loop

    End Sub
End Class

PS I missed dbasnett's post for some reason. That example is probably better as it does not loop so much.