C#基于Extension Method(扩展方法)获得文件大小的方法

/// <summary>/// Gets a files formatted size./// </summary>/// <param name="file">The file to return size of.</param>/// <returns></returns>public static string GetFileSize(this FileInfo file){ try {  //determine all file sizes  double sizeinbytes = file.Length;  double sizeinkbytes = Math.Round((sizeinbytes / 1024));  double sizeinmbytes = Math.Round((sizeinkbytes / 1024));  double sizeingbytes = Math.Round((sizeinmbytes / 1024));  if (sizeingbytes > 1)   return string.Format("{0} GB", sizeingbytes);   //returns size in gigabytes  else if (sizeinmbytes > 1)   return string.Format("{0} MB", sizeinmbytes);   //returns size in megabytes if less than one gigabyte  else if (sizeinkbytes > 1)   return string.Format("{0} KB", sizeinkbytes);   //returns size in kilabytes if less than one megabyte  else   return string.Format("{0} B", sizeinbytes);   //returns size in bytes if less than one kilabyte } catch { return "Error Getting Size"; } //catches any possible error and just returns error getting size}