SortTree(CurriculumTreeView);

private void SortTree(TreeView tv)
    {
        if (tv.Nodes != null)
        {
            for (int i = 0; i < tv.Nodes.Count; i++)
            {
                TreeNode node = tv.Nodes[i];
                SortNode(node);
            }
        }
    }

private void SortNode(TreeNode node)
    {
        if (node.ChildNodes != null && node.ChildNodes.Count > 1)
        {
            for (int i = 0; i < node.ChildNodes.Count; i++)
            {
                TreeNode childNode = node.ChildNodes[i];
                SortNode(childNode);
                SortNodes(node.ChildNodes);
            }
        }
    }

private void SortNodes(TreeNodeCollection nodes)
    {
        if (nodes == null || nodes.Count < 2)
        {
            return;
        }
        for (int i = 0; i < nodes.Count - 1; i++)
        {
            for (int j = 0; j < nodes.Count - 1; j++)
            {
                TreeNode node = nodes[j];
                TreeNode nextNode = nodes[j + 1];
                if (node.Text.CompareTo(nextNode.Text) > 0)
                {
                    TreeNode tempNode = new TreeNode();
                    tempNode = nextNode;
                    nodes.Remove(nextNode);
                    nodes.AddAt(i, tempNode);
                }
            }
        }
    }