Winform Treeview find node by tag

Question

I have a treeview where the display member could possibly have duplicates, and the tag would not. Example:

TreeNode node = new TreeNode(itemName);
node.Tag = itemID; //unique ID for the item
treeView1.Nodes.Add(node);

So, when searching, I know I can search by the itemName by using

treeView1.Nodes.Find(itemName, true);

But how could I go about searching via the tag? There's no definition for treeView1.Nodes.Where, so no linq for me :(

Any suggestions on how to search by the tag? :) Thank you!

Answer 1

Try this:

var result = treeView1.Nodes.OfType<TreeNode>()
                            .FirstOrDefault(node=>node.Tag.Equals(itemID));

NOTE: Because you said your itemID is unique, so you can use FirstOrDefault to search for the unique item. If it's not found the result will be null.

UPDATE

To search for all the nodes at all levels, you can try using some recursive method, like this:

public TreeNode FromID(string itemId, TreeNode rootNode){
   foreach(TreeNode node in rootNode.Nodes){
     if(node.Tag.Equals(itemId)) return node;
     TreeNode next = FromID(itemId, node);
     if(next != null) return next;
   }
   return null;
}
//Usage    
TreeNode itemNode = null;
foreach(TreeNode node in treeView1.Nodes){
  itemNode = FromID(itemId, node);
  if(itemNode != null) break;
}