两种取得硬盘剩余空间方法

取出来的单位是B：）

    [DllImport( " kernel32.dll " )]
     private   static   extern   bool  GetDiskFreeSpaceEx(
         string  lpDirectoryName,  out   ulong  lpFreeBytesAvailable,  out   ulong  lpTotalNumberOfBytes,  out   ulong  lpTotalNumberOfFreeBytes);

     ///   <summary>
     ///  取得磁盘剩余空间
     ///   </summary>
     ///   <param name="driveDirectoryName"> 驱动器名 </param>
     ///   <returns> 剩余空间 </returns>
     private   static   ulong  GetFreeSpace( string  driveDirectoryName)
    {
         ulong  freeBytesAvailable, totalNumberOfBytes, totalNumberOfFreeBytes;
         if  ( ! driveDirectoryName.EndsWith( " :\\ " ))
        {
            driveDirectoryName  +=   " :\\ " ;
        }
        GetDiskFreeSpaceEx(driveDirectoryName,  out  freeBytesAvailable,  out  totalNumberOfBytes,  out  totalNumberOfFreeBytes);
         return  freeBytesAvailable;
    }

     ///   <summary>
     ///  取得磁盘剩余空间
     ///   </summary>
     ///   <param name="driveDirectoryName"> 驱动器名 </param>
     ///   <returns> 剩余空间 </returns>
     private   static   ulong  GetFreeSpace( string  driveDirectoryName)
    {
         ulong  freefreeBytesAvailable  =   0 ;

        DriveInfo drive  =   new  DriveInfo(driveDirectoryName);

        freefreeBytesAvailable  =  ( ulong )drive.AvailableFreeSpace;

         return  freefreeBytesAvailable;
    }