JD2022-TU1/main/tools/framework/JD.WinFormExtensions/TreeViewExtensions.cs

using System.Collections.Generic;
using System.Windows.Forms;

namespace JD.WinFormExtensions
{
    public static class TreeViewExtensions
    {
        #region Methods

        public static IEnumerable<TreeNode> GetAllNodes(this TreeView treeView)
        {
            foreach (TreeNode treeNode in treeView.Nodes)
            {
                yield return treeNode;

                foreach (TreeNode subNode in GetAllNodesFrom(treeNode))
                {
                    yield return subNode;
                }
            }
        }

        public static IEnumerable<TreeNode> GetAllNodesFrom(TreeNode rootNode)
        {
            foreach (TreeNode treeNode in rootNode.Nodes)
            {
                yield return treeNode;

                foreach (TreeNode subNode in GetAllNodesFrom(treeNode))
                {
                    yield return subNode;
                }
            }
        }

        #endregion
    }
}