遍历文件夹找到 扩展名为 fileextension的文件路径

   public string ergodicPath(string path,string fileExtension,out string filename)
        {
            DirectoryInfo TheFolder=new DirectoryInfo(path);
            foreach (FileInfo fi in TheFolder.GetFiles())//先遍历当前目录，在遍历文件夹的每个目录
            {

                if (fi.Extension == fileExtension)
                {
                    filename = fi.Name;
                    return fi.DirectoryName;
                }
            }
            DirectoryInfo[] dirInfo = TheFolder.GetDirectories();
                        //遍历文件夹
             foreach(DirectoryInfo NextFolder in dirInfo)
                        {

                            FileInfo[] fileInfo = NextFolder.GetFiles();
                                    //遍历文件
                              foreach (FileInfo NextFile in fileInfo)
                                {
                                    if (NextFile.Extension == fileExtension)
                                    {
                                        filename = NextFile.Name;
                                        return NextFile.DirectoryName;
                                    }
                                }
                        }
             filename = string.Empty;
            return string.Empty;
          
 
        }