how to Check All and Uncheck All in TreeView1 By Click on Button1 in vb.net?

Question

Hi all
how to Check All and Uncheck All in TreeView1 By Click on Button1 in vb.net?
See This Pic and help me
thanks all

Answer 1

Unfortunately there is no easy way to do that other than to manually enumerate the children. The easiest approach is to listen for the AfterCheck event on the treeview. When it fires then enumerate the child nodes using Nodes property and check/uncheck each child. Since you've hooked the event that would recursively call the handler for each child.

   Public Class Form1  
       Private Sub OnAfterCheck(sender As Object, e As TreeViewEventArgs) Handles TreeView1.AfterCheck  
           For Each child As TreeNode In e.Node.Nodes  
               child.Checked = e.Node.Checked  
           Next  
       End Sub  
   End Class  

If you wanted to make this reusable then you could wrap this logic into a derived TreeView class.

Note that this might not perform well if the treeview is large and it doesn't handle virtual items.

Answer 2

Give this a try,

    Private Sub btnCheckAll_Click(sender As Object, e As EventArgs) Handles btnCheckAll.Click  
        SetCheckState(TreeView1, True)  
    End Sub  
  
    Private Sub btnUn_Click(sender As Object, e As EventArgs) Handles btnUn.Click  
        SetCheckState(TreeView1, False)  
    End Sub  
  
    Private Sub SetCheckState(tv As TreeView, checkState As Boolean)  
        SetNode(tv.Nodes(0), checkState)  
    End Sub  
  
    Private Sub SetNode(Node As TreeNode, checkState As Boolean)  
        Node.Checked = checkState  
        ' Node.EnsureVisible() ' for debug  
        For Each nd As TreeNode In Node.Nodes  
            SetNode(nd, checkState)  
        Next  
    End Sub