Question

First off we have the almighty code!

List nodes = new List();
TreeNode Temp = new TreeNode();

TreeNodeCollection nodeList = treeViewTab4DirectoryTree.Nodes;

while (nodeList.Count != 0)
{
    Temp = nodeList[0];

    while (Temp.FirstNode != null)
    {
        Temp = Temp.FirstNode;
    }

    if (!nodes.Contains(Temp.FullPath))
    {
        nodes.Add(Temp.Text);
    }

    nodeList.Remove(Temp);
}

Now the problem: I have written the code above with the intent of creating a List containing the text from all the nodes in the tree. That works perfectly. The problem I am having is when I remove the nodes from my variable they are also being removed from the actual list. The question would be how can I make a copy of the list of nodes so I can play with them without messing with the ACTUAL list. How do I make a copy of it without just making a reference to it? Any help will be greatly appreciated!

Answer 1

Your problem arises because “nodeList” is a reference to treeViewTab4DirectoryTree.Nodes, rather than a copy of it.

The solution depends entirely on the what type of TreeNodeCollection you’re using (WinForms, ASP.net, something else?), as you’ll need to look for a .Copy(), .Clone(), .ToArray() method or similar to take a copy of the contents of the collection, rather than a reference to the existing collection.

If, for example, you’re using asp.net and thus the System.Web.UI.WebControls.TreeNodeCollection, you could use the .CopyTo method in a way similar to this:

TreeNode[] x = null;
treeViewTab4DirectoryTree.Nodes.CopyTo(x, 0);