How to search multiple treeview nodes at a particular depth - vb.net

Question

Please does anyone know how I can search the text of multiple treeview nodes at a particular depth on the click of a button? The treeview nodes are arranged as follows:
I want to prevent the user from entering duplicate grandchild nodes of the same title into the treeview, i.e entering 'Movie 2' a second time should throw up a message that Movie 2 has already been entered; if not, then add the new movie title.
The grandchild node titles are fed into the treeview from a textbox. I am using Visual Basic 2010 Express. Thank you in advance.
The code I am using is:
Private Sub Button11_Click(sender As System.Object, e As System.EventArgs) Handles Button11.Click
'New movie title has been introduced into the study
Dim SelectedNode As TreeNode
SelectedNode = TreeView1.SelectedNode
'To avoid entering duplicate movies title
Dim NewMovieName As String = TextBox1.Text.Trim.ToLower ' The content of that node
Dim parentNode = SelectedNode.Parent ' Get the parent
Dim childNodes As TreeNodeCollection = parentNode.Nodes ' Get all the children
Dim WeHaveDuplicate As Boolean = False ' We use this to flag if a duplicate is found. Initially set to false.
For Each tempNode As TreeNode In childNodes
'Test that we have the same name but not referring to the same node
If tempNode.Text.Trim.ToLower = NewMovieName And tempNode IsNot parentNode Then WeHaveDuplicate = True
Next
If WeHaveDuplicate = True Then
'Send message to user
MsgBox(TextBox1.Text & " as a parameter has already been considered.", vbOKOnly)
Exit Sub
Else
parentNode.Nodes.Add(TextBox1.Text)
TreeView1.ExpandAll()
End If
Exit Sub
End Sub
All help would be greatly appreciated. Thank you.

Answer 1

Here is a little snippet that I use frequently. It will find a node by it's text. It will also highlight and expand the node found.
Notice it is recursive, so it will search to the bottom of the supplied node collection (param). If this supplied collection is the root node, then it will search the whole tree.
I usually apply a unique string to the node.tag property. If you adjust the function to look for that, you can have duplicate text displaying while still having a unique string to look for...
''' <summary>
''' Find and Expand Node in Tree View
''' </summary>
Private Function FindNode(ByVal SearchText As String, ByVal NodesToSearch As TreeNodeCollection, ByVal TreeToSearch As TreeView) As TreeNode
Dim ReturnNode As TreeNode = Nothing
Try
For Each Node As TreeNode In NodesToSearch
If String.Compare(Node.Text, SearchText, True) = 0 Then
TreeToSearch.SelectedNode = Node
Node.Expand()
ReturnNode = Node
Exit For
End If
If ReturnNode Is Nothing Then ReturnNode = FindNode(SearchText, Node.Nodes, TreeToSearch)
Next
Catch ex As Exception
Throw
End Try
Return ReturnNode
End Function
Edited:
Per your recent comment,
You might try using it like this...
WeHaveDuplicate = (FindNode("Movie 2", TreeView1.Nodes, TreeView1) Is Nothing)
If WeHaveDuplicate = True Then
'message user of dupe
Else
'add movie
End If