Need help with Tree View Control

[hellswraith]

I need some help with the Tree View control. I set the properties so that the nodes have check boxes next to them.

When the parent node is checked, I want all the child nodes of that parent to be checked. Same with unchecking them. I won't know for sure how many child nodes there are. How do I do this in code, and do I do it in the NodeCheck event?

Some sample code would be a great help. Thanks.

[gdebacker]

Try this code...

Public Sub CheckNodes(MyTreeView As TreeView, ByVal Node As MSComctlLib.Node, bChecked As Boolean)
    Dim iIndex As Integer
    If Not Node Is Nothing Then
        If Node.Children > 0 Then
            iIndex = Node.Child.Index
            Node.Child.Checked = bChecked
            CheckNodes MyTreeView, Node.Child, bChecked
            While iIndex <> Node.Child.LastSibling.Index
                MyTreeView.Nodes(iIndex).Next.Checked = bChecked
                iIndex = MyTreeView.Nodes(iIndex).Next.Index
                CheckNodes MyTreeView, MyTreeView.Nodes(iIndex).Next, bChecked
            Wend
            CheckNodes MyTreeView, Node.Child.Next, bChecked
        Else
            Node.Checked = bChecked
        End If
    End If
End Sub

Call from the TreeView_NodeCheck event like this

Private Sub TreeView1_NodeCheck(ByVal Node As MSComctlLib.Node)
    CheckNodes TreeView1, Node, Node.Checked
End Sub

Greg

[hellswraith]

Thanks a lot for your help, it works great.

[BruceG]

hellswraith, be advised that MS acknowledges a bug in the TV control when checkboxes are used. They advise setting the Checkbox style of the TreeView by using API calls, rather than simply setting the "Checkboxes" property to True.

In a module, you would need:

    Public Const TVS_CHECKBOXES As Long = &H100
    Public Const GWL_STYLE      As Long = (-16)

    Public Declare Function GetWindowLong _
        Lib "user32" Alias "GetWindowLongA" _
        (ByVal hwnd As Long, _
         ByVal nIndex As Long) As Long

    Public Declare Function SetWindowLong _
        Lib "user32" Alias "SetWindowLongA" _
        (ByVal hwnd As Long, _
         ByVal nIndex As Long, _
         ByVal dwNewLong As Long) As Long

In your form (probably in the Load event), you would need:

    Dim lngCurStyle As Long
    Dim lngResult As Long
    ' === Set the Checkbox style of the TreeView ===
    ' As advised by Microsoft, due to a bug in the TreeView control,
    ' set the Checkbox style of the TreeView by using the following
    ' API calls, rather than simply setting the "Checkboxes" property
    ' to True ...
    lngCurStyle = GetWindowLong(tvwGlobalUpdate.hwnd, GWL_STYLE)
    lngResult = SetWindowLong(tvwGlobalUpdate.hwnd, GWL_STYLE, _
                              lngCurStyle Or TVS_CHECKBOXES)

Here's a link to the MS article:
http://support.microsoft.com/support.../Q192/1/88.asp

[hellswraith]

Thanks, I would probably would have been beating my head trying to figure out what is wrong if something happened. Good lookin out for me. That is why this forum is as good as it is.