this example is from MSDN.
(
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html
/frlrfsystemwindowsformstreeviewclassafterchecktopic.asp)
Private Sub CheckAllChildNodes(treeNode As TreeNode, nodeChecked As Boolean)
Dim node As TreeNode
For Each node In treeNode.Nodes
node.Checked = nodeChecked
If node.Nodes.Count > 0 Then
' If the current node has child nodes, call the CheckAllChildsNodes
method recursively.
Me.CheckAllChildNodes(node, nodeChecked)
End If
Next node
End Sub
' NOTE This code can be added to the BeforeCheck event handler instead of
the AfterCheck event.
' After a tree node's Checked property is changed, all its child nodes are
updated to the same value.
Private Sub node_AfterCheck(sender As Object, e As TreeViewEventArgs)
Handles treeView1.AfterCheck
' The code only executes if the user caused the checked state to change.
If e.Action <> TreeViewAction.Unknown Then
If e.Node.Nodes.Count > 0 Then
' Calls the CheckAllChildNodes method, passing in the current
' Checked value of the TreeNode whose checked state changed.
Me.CheckAllChildNodes(e.Node, e.Node.Checked)
End If
End If
End Sub
