/// <summary>
        /// 构造函数。
        /// </summary>
        /// <param name="filePath">文件路径。</param>
        /// <param name="loadType">加载方式。</param>
        /// <param name="fileKeyType">缓存键类型。</param>
        public FileCacheItem(string filePath, DataLoadType loadType, CacheKeyType fileKeyType)
        {
            this.FilePath = filePath;
            if (!File.Exists(this.FilePath))
            {
                throw new ArgumentException(filePath + " 文件不存在!");
            }
            this.FileLoadType = loadType;
            this.FileKeyType = fileKeyType;
            this.FileName = Path.GetFileNameWithoutExtension(this.FilePath);
            this.FileExtension = Path.GetExtension(this.FilePath);
            this.LastAccessDate = DateTime.Now;
            this.ItemSize = new FileInfo(this.FilePath).Length;
            this.ItemKey = this.FilePath;

            if (this.FileKeyType == CacheKeyType.MD5 || this.FileLoadType == DataLoadType.Load)
            {
                using (FileStream fstream = new FileStream(this.FilePath, FileMode.Open, FileAccess.Read, FileShare.Read))
                {
                    if (this.FileKeyType == CacheKeyType.MD5)
                    {
                        this.ItemKey = iPower.Cryptography.HashCrypto.HashFile(fstream, "md5");
                        fstream.Seek(0, SeekOrigin.Begin);
                    }
                    if (this.FileLoadType == DataLoadType.Load)
                    {
                        using (BufferBlockUtil block = new BufferBlockUtil())
                        {
                            byte[] buf = new byte[1024];
                            int len = 0;
                            while ((len = fstream.Read(buf, 0, buf.Length)) > 0)
                            {
                                block.Write(buf, 0, len);
                            }
                            this.FileBytes = block.ToArray();
                        }
                    }
                    fstream.Close();
                }
            }
        }
 /// <summary>
 /// 下载文件。
 /// </summary>
 /// <param name="fileName">文件名称。</param>
 /// <returns>文件数据。</returns>
 public byte[] Download(string fileName)
 {
     if (string.IsNullOrEmpty(fileName)) throw new ArgumentNullException("fileName", "文件名不能为空!");
     byte[] data = null;
     string path = Path.GetFullPath(this.root + "\\" + fileName);
     if (File.Exists(path))
     {
         using (BufferBlockUtil block = new BufferBlockUtil())
         {
             using (FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read))
             {
                 int count = 0;
                 byte[] buffer = new byte[1024];
                 while ((count = fs.Read(buffer, 0, buffer.Length)) > 0)
                 {
                     block.Write(buffer, 0, count);
                 }
                 fs.Close();
             }
             data = block.ToArray();
         }
     }
     return data;
 }
 /// <summary>
 /// 延时加载数据。
 /// </summary>
 internal void DelayLoad()
 {
     if ((this.FileBytes == null || this.FileBytes.Length == 0) && (this.FileLoadType == DataLoadType.DelayLoad) && File.Exists(this.FilePath))
     {
         using (FileStream fstream = new FileStream(this.FilePath, FileMode.Open, FileAccess.Read, FileShare.Read))
         {
             using (BufferBlockUtil block = new BufferBlockUtil())
             {
                 byte[] buf = new byte[1024];
                 int len = 0;
                 while ((len = fstream.Read(buf, 0, buf.Length)) > 0)
                 {
                     block.Write(buf, 0, len);
                 }
                 this.FileBytes = block.ToArray();
             }
         }
     }
 }