C# 获取本地磁盘驱动器、U盘、共享目录所在驱动器的大小

string filePathRoot = Path.GetPathRoot(fileName);
                    if (!filePathRoot.EndsWith("\\"))
                    {
                        filePathRoot = filePathRoot + "\\";
                    }

DriveType driveType = (DriveType)GetDriveType(filePathRoot);

                    if (driveType == DriveType.FixedDisk || driveType == DriveType.FloppyOrUsb)  //本地磁盘驱动器或usb、软盘
                    {
                    }
                    else if(driveType == DriveType.NetDisk) //网络共享文件夹所在磁盘大小   
                    {
                    }

[DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        public static extern int GetDriveType(string driveinfo);

        private enum DriveType
        {
            NotExist = 1,
            FloppyOrUsb = 2,
            FixedDisk = 3,
            NetDisk = 4,
            CDRom = 5,
            RAMDisk = 6
        }

///   
        /// 获取指定驱动器的剩余空间总大小(单位为B) 
        ///   
        ///  只需输入代表驱动器的字母即可  
        ///    
        public static long GetHardDiskFreeSpace(string str_HardDiskName)
        {
            long freeSpace = new long();
            if(!str_HardDiskName.EndsWith("\\"))
            {
                str_HardDiskName = str_HardDiskName + ":\\";
            }
            System.IO.DriveInfo[] drives = System.IO.DriveInfo.GetDrives();
            foreach (System.IO.DriveInfo drive in drives)
            {
                if (drive.Name == str_HardDiskName)
                {
                    freeSpace = drive.TotalFreeSpace;
                }
            }
            return freeSpace;
        }

[SuppressMessage("Microsoft.Security", "CA2118:ReviewSuppressUnmanagedCodeSecurityUsage"), SuppressUnmanagedCodeSecurity]
        [DllImport("Kernel32", SetLastError = true, CharSet = CharSet.Auto)]
        [return: MarshalAs(UnmanagedType.Bool)]

        public static extern bool GetDiskFreeSpaceEx
        (
            string lpszPath,                    // Must name a folder, must end with '\'.
            ref long lpFreeBytesAvailable,
            ref long lpTotalNumberOfBytes,
            ref long lpTotalNumberOfFreeBytes
        );