Loop through all treeview items recursive

Question

3.50/5 (2 votes)

See more:

I need a function which loops through all TreeViewItems and give beak the TreeViewItem which got a specific Header...

For example:

GetSearchedTreeViewItemByHeader(string _header)
{
  var searchedNode = new TreeViewItem();
  foreach(var node in treeView.Items)
  {
   if(node.Header == _header)
   {
    searchedNode = node
   }
  }

  return searchedNode
}

this only works for the first Item in the treeView, does anybody know how i loop through all items(also all childitems...)? i got no idea i only heard from a recursive solution but i dont know how to do it...

thanks in advance!

EDIT:
I use WPF

What I have tried:

TreeViewItems.Items check, for loop, while loop

Posted 6-Jul-17 4:05am

Member 12969975

Updated 10-Jul-17 4:43am

v2

Add a Solution

Comments

Richard Deeming 6-Jul-17 11:21am

Are you looking for one matching node, or all matching nodes?

Member 12969975 7-Jul-17 2:59am

one matching node

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

KarstenK · Answer 1 · 2017-07-06T05:44:00

Solution 1

The recursion on that task is so common that even Microsoft has published a recursice code snippet.

tip: if you search a specific item, you use it as additional input parameter.

Posted 6-Jul-17 5:44am

KarstenK

Richard Deeming · Answer 2 · 2017-07-06T05:46:00

Here's a generic extension method to iterate all nodes in any hierarchy:

private static IEnumerable<T> SelectRecursiveIterator<T>(IEnumerable<T> source, Func<T, IEnumerable<T>> getChildren)
{
    var stack = new Stack<IEnumerator<T>>();

    try
    {
        stack.Push(source.GetEnumerator());
        while (stack.Count != 0)
        {
            IEnumerator<T> iter = stack.Peek();
            if (iter.MoveNext())
            {
                T current = iter.Current;
                yield return current;

                IEnumerable<T> children = getChildren(current);
                if (children != null) stack.Push(children.GetEnumerator());
            }
            else
            {
                iter.Dispose();
                stack.Pop();
            }
        }
    }
    finally
    {
        while (stack.Count != 0)
        {
            stack.Pop().Dispose();
        }
    }
}

public static IEnumerable<T> SelectRecursive<T>(this IEnumerable<T> source, Func<T, IEnumerable<T>> getChildren)
{
    if (source == null) throw new ArgumentNullException(nameof(source));
    if (getChildren == null) return source;
    return SelectRecursiveIterator(source, getChildren);
}

With that in place, you can iterate all the nodes in your tree, and return either all matching nodes:

static IEnumerable<TreeNode> FindAllNodesByHeader(TreeView tree, string header)
{
    return tree.Items.Cast<TreeViewItem>().SelectRecursive(node => node.Items.Cast<TreeViewItem>()).Where(node => node.Header == header);
}

or just the first matching node:

static TreeNode FindFirstNodeByHeader(TreeView tree, string header)
{
    return tree.Items.Cast<TreeViewItem>().SelectRecursive(node => node.Items.Cast<TreeViewItem>()).FirstOrDefault(node => node.Header == header);
}