System.IO.FileInfo[] Files = directory.GetFiles();
    for (int FileCount = 0; FileCount < Files.Length; FileCount++)
    {
        **lblTest.Text = lblTest.Text +"<br>"+ Path.GetFullPath(Files[FileCount].ToString());**
        DirNode.ChildNodes.Add(new TreeNode(Files[FileCount].Name));
    }

lblTest.Text += Files[FileCount].FullName;