C# - Recursive File Search

        private List<string> RecursiveDirectoryFind(string directory, string searchpattern)
        {
            List<string> paths = new List<string>(), _temp;
 
            //Go through each directory first
            DirectoryInfo di = new DirectoryInfo(directory);
            DirectoryInfo[] _di = di.GetDirectories();
            foreach (DirectoryInfo __di in _di)
            {
                this.Update();
                _temp = RecursiveDirectoryFind(__di.FullName, searchpattern);
                foreach (string s in _temp)
                {
                    paths.Add(s);
                }
            }
 
            //Go through the files in the current directory
            FileInfo[] fi = di.GetFiles(searchpattern);
            foreach (FileInfo f in fi)
            {
                this.Update();
                paths.Add(f.FullName);
            }
 
            return paths;
        }