Looping through nodes in a tree

Posted on 2006-11-17
Last Modified: 2007-12-19
I have a VB6 program with a tree in a form. I already have the tree all populated. What I want to do know is build in the logic that if all of the children of a parent are checked then the parent itself will be checked, or true. If someone could please point me in the right direction with a sample of code, that would be great. Thanks, arajoe.
Question by:arajoe
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
LVL 143

Assisted Solution

by:Guy Hengel [angelIII / a3]
Guy Hengel [angelIII / a3] earned 50 total points
ID: 17968422
this recursive sub would set the same checked value for all the children by the parent's checked value.

public Sub CheckChildren ( byval n as node )
  dim c as Node

  set c = n.Child
  while not ( c is nothing )
    c.checked = n.checked
    checkchildren c

    set c = c.nextsibling

end sub
LVL 13

Accepted Solution

jmundsack earned 350 total points
ID: 17968691
Drop a treeview on a form and paste in this code:

Option Explicit

Private Sub Form_Load()
    Dim nod As Node
    With TreeView1
        Set nod = .Nodes.Add(, tvwFirst, "fruit", "Fruit")
        nod.Expanded = True
        .Nodes.Add "fruit", tvwChild, "apple", "Apple"
        .Nodes.Add "fruit", tvwChild, "banana", "Banana"
        .Nodes.Add "fruit", tvwChild, "orange", "Orange"
        Set nod = .Nodes.Add(, tvwFirst, "veg", "Vegetable")
        nod.Expanded = True
        .Nodes.Add "veg", tvwChild, "asparagus", "Asparagus"
        .Nodes.Add "veg", tvwChild, "cucumber", "Cucumber"
        .Nodes.Add "veg", tvwChild, "zucchini", "Zucchini"
    End With
End Sub

Private Sub TreeView1_NodeCheck(ByVal Node As MSComctlLib.Node)
    Dim nod As Node
    Dim blnAll As Boolean
    If Node.Children > 0 Then
        Set nod = Node.Child
        Do While Not nod Is Nothing
            nod.Checked = Node.Checked
            Set nod = nod.Next
    End If
    If Not Node.Parent Is Nothing Then
        blnAll = True
        Set nod = Node.Parent.Child
        Do While Not nod Is Nothing
            If Not nod.Checked Then
                blnAll = False
                Exit Do
            End If
            Set nod = nod.Next
        Node.Parent.Checked = blnAll
    End If
End Sub

LVL 86

Assisted Solution

by:Mike Tomlinson
Mike Tomlinson earned 50 total points
ID: 17969104
LVL 28

Assisted Solution

Ark earned 50 total points
ID: 17969674
Another approach can be used if you have no duplicate nodes in each level in treeview:

Private Sub Form_Load()
   Dim nd As Object, ndParent As Object
   Dim i As Long, j As Long, k As Long
   For i = 1 To 5
      Set ndParent = TreeView1.Nodes.Add(, , , "Node Level 1 #" & i)
      For j = 1 To 5
          Set nd = TreeView1.Nodes.Add(ndParent, tvwChild, , "Node Level 2 #" & j)
          For k = 1 To 5
              Call TreeView1.Nodes.Add(nd, tvwChild, , "Node Level 3 #" & j)
          Next k
      Next j
   Next i
End Sub

Private Sub TreeView1_NodeCheck(ByVal Node As Node)
   Dim sPath As String, length As Long
   sPath = Node.FullPath
   length = Len(sPath)
   For Each nd In TreeView1.Nodes
       If Len(nd.FullPath) >= length Then
          If Left(nd.FullPath, length) = sPath Then
             nd.Checked = Node.Checked
          End If
       End If
End Sub

Author Comment

ID: 17980060
Thanks to everyone. I went with the answer I did because it allowed for a more recursive function. The code I ended up with is below. Thanks again, arajoe.

Private Sub Check_Parents(ByRef Node As MSComctlLib.Node, ByVal Node_Checked_Value As Boolean)

    Dim Child As MSComctlLib.Node
    Dim All_Checked As Boolean
    If Node.Children > 0 Then
        Set Child = Node.Child
        Do While Not Child Is Nothing
            Child.Checked = Node_Checked_Value
            UnAssign_SUP Child
            Check_Parents Child, Child.Checked
            Set Child = Child.Next
    End If
    If Not Node.Parent Is Nothing Then
        All_Checked = True
        Set Child = Node.Parent.Child
        Do While Not Child Is Nothing
            If Not Child.Checked Then
                All_Checked = False
                Exit Do
            End If
            Set Child = Child.Next
        Node.Parent.Checked = All_Checked
    End If
End Sub

Featured Post

Salesforce Has Never Been Easier

Improve and reinforce salesforce training & adoption using WalkMe's digital adoption platform. Start saving on costly employee training by creating fast intuitive Walk-Thrus for Salesforce. Claim your Free Account Now

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Enums (shorthand for ‘enumerations’) are not often used by programmers but they can be quite valuable when they are.  What are they? An Enum is just a type of variable like a string or an Integer, but in this case one that you create that contains…
I was working on a PowerPoint add-in the other day and a client asked me "can you implement a feature which processes a chart when it's pasted into a slide from another deck?". It got me wondering how to hook into built-in ribbon events in Office.
Get people started with the utilization of class modules. Class modules can be a powerful tool in Microsoft Access. They allow you to create self-contained objects that encapsulate functionality. They can easily hide the complexity of a process from…
This lesson covers basic error handling code in Microsoft Excel using VBA. This is the first lesson in a 3-part series that uses code to loop through an Excel spreadsheet in VBA and then fix errors, taking advantage of error handling code. This l…
Suggested Courses
Course of the Month5 days, 18 hours left to enroll

626 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question