Tree View

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        TreeView1.ExpandAll()
    End Sub

لغلق الكل

 Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        TreeView1.CollapseAll()
    End Sub