public class LhaUtity
    {
        ///取得DLL的版本
        [DllImport("unlha32")]
        private static extern UInt16 UnlhaGetVersion();

        /// <summary>
        /// '取得DLL的執行情況
        /// </summary>
        /// <returns>是否成功</returns>
        [DllImport("unlha32")]
        private static extern  Boolean UnlhaGetRunning();

        /// <summary>
        /// '文件檢查
        /// </summary>
        /// <param name="szFileName"></param>
        /// <param name="iMode"></param>
        /// <returns></returns>
        [DllImport("unlha32")]
        private static extern Boolean UnlhaCheckArchive(String szFileName, Int32 iMode);

        /// <summary>
        /// 文件解壓縮
        /// </summary>
        /// <param name="hwnd"></param>
        /// <param name="szCmdLine"></param>
        /// <param name="szOutput"></param>
        /// <param name="dwSize"></param>
        /// <returns></returns>
        [DllImport("unlha32")]
        private static extern int Unlha(int hwnd, string szCmdLine, string szOutput, int dwSize);

        /// <summary>
        /// 需要解壓的文件
        /// </summary>
        /// <param name="archiveFile">解壓文件路徑</param>
        /// <param name="extractDir">解壓到路徑</param>
        /// <param name="isDeleteFile">是否刪除</param>
        public static bool UnCompress(string archiveFile, string extractDir,bool  isDeleteFile)
        {
            string extractFullPath = string.Empty;
            string startPath = AppDomain.CurrentDomain.BaseDirectory;

            if (!System.IO.File.Exists(archiveFile))
            {
                //判斷需要解壓的文件存不存
                throw new Exception(string.Format("需要解壓的{0}不存在", archiveFile));
            }

            try
            {
                UInt16 ver = LhaUtity.UnlhaGetVersion();
            }
            catch (Exception ex)
            {
                throw new Exception("沒找到Unlha32.dll文件");
            }

            if (UnlhaGetRunning())
            {
                throw new Exception("DLL正在執行");
            }

            if (!UnlhaCheckArchive(archiveFile, 0))
            {
                throw new Exception("文件不能被解壓縮");
            }

            //解壓的路徑
            if (string.IsNullOrEmpty(extractDir))
            {
                extractFullPath =string.Format(@"{0}{1}\", startPath,archiveFile.Substring(archiveFile.LastIndexOf("\\")+1,archiveFile.IndexOf(".lha")-1-archiveFile.LastIndexOf("\\")));
            }
            else
            {
                extractFullPath = extractDir;
            }

            if (!System.IO.Directory.Exists(extractFullPath))
            {
                System.IO.Directory.CreateDirectory(extractFullPath);
            }
              

            int ret = Unlha(0, string.Format("x \"{0}\" \"{1}\"", archiveFile, extractFullPath), null, 0);

            if (ret != 0)
            {

                if (ret == 32800)
                {
                    throw new Exception("文件解壓縮取消");
                }
                else
                {
                    throw new Exception("文件解壓縮異常結束");

                }

            }
            else
            {
                if (isDeleteFile)
                {
                    System.IO.File.Delete(archiveFile);
                }

                return true;
            }

        }

}