how to set treeview child nodes of child nodes of child nodes ... etc.. in loop

Question

I am doing a foreach loop where I add nodes to a treeview control. When

            TreeNode treeNode;

            foreach (Item item in stuff)
            {
                      treeNode = this.TreeView.Nodes.Add("label");
            }

What I want to do is put a conditional in the loop that, if true, it adds any following nodes in the loop as child nodes to that treeNode where the conditional is true. I can do this for a single occurence where the conditional is true, but how can I do it if it is true WITHIN a node that is already a child? Ie. make a child node of a child node of a child node and so on... instead of doing it manually like Nodes.Nodes.Nodes.Nodes. etc...

Thanks

giangurgolo · Answer

Thanks these helped a lot!

Matthew Cochran · Answer

You are probably using Studio2005 and .NET 2.0 so you don't have lambda expressions available. You can use an anonymous delegate like this: ModifyCollection(tv.Nodes delegate ( TreeNodeCollection c) { if (c.Count == 4) // test c.Add( SAMPLE TEXT ); // add items here based on conditions }); or you can explicitly define the method: private void DoSomethingTo( TreeNodeCollection c) { if (c.Count == 4) // test c.Add( SAMPLE TEXT ); // add items here based on conditions } And call it like this: ModifyCollection(tv.Nodes DoSomethingTo); They are all different ways to do the same thing. Let me know if these worked for you. -Matt

giangurgolo · Answer

Thanks. But I get an error from the => (after collection its underlined with red). Is there a using I need to add to the class? Here is my code: private void InitializeScriptEditor() { this.ScriptTree.Nodes.Clear(); TreeNode treeNode; foreach (ScriptCommand bsc in commands) { treeNode = this.ScriptTree.Nodes.Add( whatever ); if (bsc.CommandID == 0xFC) ; // add the nodes as child nodes here } } Once again thanks for the help.

Matthew Cochran · Answer

If you define a recursive method as follows: private void ModifyCollection( TreeNodeCollection c Action TreeNodeCollection > visitor) { visitor(c); foreach ( TreeNode node in c) ModifyCollection(node.Nodes visitor); } You could recursively go through each collection and add nodes based on some condition (you can use a anonymous delegate as in the following code or create a seperate method to handle the test and adding of nodes that is supposed to be repeated). TreeView tv = new TreeView (); ModifyCollection(tv collection => { if (collection.Count == 4) // test collection.Add( SAMPLE TEXT ); // add items here based on conditions }); You could use the same technique to go through the Nodes instead of the collections (define a recursive method with a Node as input parameter instead of the collection).