How to search within a Tree

Is it possible to search for a treenode within in tree by the treenode text?  I have a windows form application C# application that allows users to create new tree nodes and assign ID as text.  I need to make sure the ID value they assign is unique within the parent.  

For example,

Tree
   - Category 1   (ID = 001)
      - SubCat 1   (ID = 031)
      - SubCat 2   (ID = 091)
      - SubCat 3   (ID =   ---->  If the user trys to enter 091, 031 or 001 for the ID, then I need to                                           display an error.  How can I search within a tree?
  -  Category 2   (ID = 004)

           
HojoformoAsked:
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anarki_jimbelConnect With a Mentor Commented:
Honestly, I would do another way. I would use a dictionary to store references to all nodes, and use id as aq key:

The idea is outlined in code below.

The main reason for that is performance. Also, it's quite handy - using an id you may find any node very quickly. Search in dictionaries MUCH faster than in trees. For big trees this might be important.My approach does not consume much additional memory.

Drawback - you need to maintain bot collections - your tree and the dictionary.
TreeView tv = new TreeView();
            Dictionary<int, TreeNode> nodeHash = new Dictionary<int, TreeNode>();

            TreeNode node = new TreeNode();
            int someNewID = 5;
            
            if(!nodeHash.ContainsKey(someNewID))
            {
                node.Text = someNewID.ToString();
                tv.Nodes.Add(node);
                nodeHash.Add(someNewID, node);
            }
            {
                MessageBox.Show("This ID already exists");
            }

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Tyler LaczkoCommented:
use embedded for loops to access the trees within the trees.

compare their values.
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Mike TomlinsonConnect With a Mentor Middle School Assistant TeacherCommented:
When you add the TreeNodes, use the ID value as the KEY:
http://msdn.microsoft.com/en-us/library/57aa8e09.aspx

Then you can use the Nodes.Find() method to determine if a node with that key already exists:
http://msdn.microsoft.com/en-us/library/system.windows.forms.treenodecollection.find.aspx
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