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

giangurgolo

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

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

giangurgolo18y ago
Thanks, these helped a lot!
0
Matthew Cochran18y ago
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
0
giangurgolo18y ago
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.
0
Matthew Cochran18y ago
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).

0