by kc7dji (1 Submission)
Category: Custom Controls/Forms/Menus
Compatability: Visual Basic 3.0
Difficulty: Intermediate
Date Added: Wed 3rd February 2021
Rating: 
(8 Votes)
This basic procedure will handle all parent and child Checkboxes in a TreeView control. If you check a child node it will automatically check the parent(s) and vise versa.
Inputs
This procedure requires you to pass in the Treeview and the current node.
Assumes
Basic TreeView(s). This code assumes you already have a TreeView populated with "CheckBoxes" turned ON.
VBcoders
'Put this call into the TreeViews NODECHECK procedure.
Private Sub MyTreeView_NodeCheck(ByVal Node As MSComctlLib.Node)
Call TreeCheckBoxes(MyTreeView, Node)
end Sub
'Add this procedure to a Module or to the form the TreeView is contained.
Public Sub TreeCheckBoxes(TR As TreeView, CurrentNode As Node)
'This code is copyright (c)2002 by Scott Durrett - All Rights Reserved
'No changes are allow without written approval from the Author.
Dim liNodeIndex As Integer
Dim lbDirty As Boolean
Dim liCounter As Integer
Dim lParentNode As Node
Dim lChildNode As Node
lbDirty = False
liNodeIndex = CurrentNode.Index
If CurrentNode.Checked = True Then 'node is checked
'Children Check/UnCheck
If Not TR.Nodes.Item(CurrentNode.Index).Child Is Nothing Then
Set lParentNode = TR.Nodes.Item(liNodeIndex).Child.FirstSibling
Do While Not lParentNode Is Nothing
lParentNode.Checked = CurrentNode.Checked
If Not lParentNode.Child Is Nothing Then
Set lChildNode = lParentNode.Child
Do While Not lChildNode Is Nothing
lChildNode.Checked = CurrentNode.Checked
If Not lChildNode.Next Is Nothing Then
Set lChildNode = lChildNode.Next
Else
Set lChildNode = lChildNode.Child
End If
Loop
End If
Set lParentNode = lParentNode.Next
Loop
End If
'============================================================
'Check all parent nodes
Do While Not TR.Nodes.Item(liNodeIndex).Parent Is Nothing
TR.Nodes.Item(liNodeIndex).Parent.Checked = CurrentNode.Checked
liNodeIndex = TR.Nodes.Item(liNodeIndex).Parent.Index
Loop
'===========================
ElseIf CurrentNode.Checked = False Then 'node is unchecked
'Children Check/UnCheck
If Not TR.Nodes.Item(CurrentNode.Index).Child Is Nothing Then
Set lParentNode = TR.Nodes.Item(liNodeIndex).Child.FirstSibling
Do While Not lParentNode Is Nothing
lParentNode.Checked = CurrentNode.Checked
If Not lParentNode.Child Is Nothing Then
Set lChildNode = lParentNode.Child
Do While Not lChildNode Is Nothing
lChildNode.Checked = CurrentNode.Checked
If Not lChildNode.Next Is Nothing Then
Set lChildNode = lChildNode.Next
Else
Set lChildNode = lChildNode.Child
End If
Loop
End If
Set lParentNode = lParentNode.Next
Loop
End If
'============================================================
Set lParentNode = Nothing
Set lChildNode = Nothing
If Not CurrentNode.Parent Is Nothing Then
Set lParentNode = CurrentNode.Parent.Child
Do While Not lParentNode Is Nothing
Set lChildNode = lParentNode.FirstSibling
Do While Not lChildNode Is Nothing
If lChildNode.Checked = True Then
lbDirty = True
Exit Do
End If
'If Not lChildNode.Next Is Nothing Then
Set lChildNode = lChildNode.Next
'End If
Loop
If lbDirty = False Then
If Not lParentNode.Parent Is Nothing Then
lParentNode.Parent.Checked = False
lbDirty = False
End If
Else
Exit Do
End If
If Not lParentNode.Parent Is Nothing Then
Set lParentNode = lParentNode.Parent
Else
Set lParentNode = lParentNode.Parent
End If
Loop
End If
End If
Set CurrentNode = Nothing
Set lParentNode = Nothing
Set lChildNode = Nothing
End Sub
'The End
