解压zip文件

    /// <summary>
    /// 执行压缩命令结果
    /// </summary>
    public enum CompressResults
    {
        Success,
        SourceObjectNotExist,
        UnKnown
    }

    /// <summary>
    /// 执行解压缩命令结果
    /// </summary>
    public enum UnCompressResults
    {
        Success,
        SourceObjectNotExist,
        PasswordError,
        UnKnown
    }
    /// <summary>
    /// 进程运行结果
    /// </summary>
    //public enum ProcessResults
    //{
    //    Success,
    //    Failed
    //}
    public class ZipOperate
    {
        #region 单例模式

        private static ZipOperate uniqueInstance;
        private static object _lock = new object();

        //private ZipOperate() { }
        public static ZipOperate getInstance()
        {
            if (null == uniqueInstance)      //确认要实例化后再进行加锁，降低加锁的性能消耗。
            {
                lock (_lock)
                {
                    if (null == uniqueInstance)
                    {
                        uniqueInstance = new ZipOperate();
                    }
                }
            }
            return uniqueInstance;
        }

        #endregion

        #region 7zZip压缩、解压方法
        /// <summary>
        /// 压缩文件
        /// </summary>
        /// <param name="objectPathName">压缩对象（即可以是文件夹|也可以是文件）</param>
        /// <param name="objectZipPathName">保存压缩文件的路径</param>
        /// <param name="strPassword">加密码</param>
        /// 测试压缩文件夹：压缩文件（objectZipPathName）不能放在被压缩文件（objectPathName）内，否则报“文件夹被另一进程使用中”错误。
        /// <returns></returns>
        public CompressResults Compress7zZip(String objectPathName, String objectZipPathName, String strPassword)
        {
            try
            {
                //http://sevenzipsharp.codeplex.com/releases/view/51254 下载sevenzipsharp.dll
                //SevenZipSharp.dll、zLib1.dll、7z.dll必须同时存在，否则常报“加载7z.dll错误”
                string libPath = @"E:\yingyong\Uncompress_7zip\Uncompress_7zip\bin\Debug\7z.dll";//System.AppDomain.CurrentDomain.BaseDirectory + @"..\..\dll\7z.dll";
                SevenZipCompressor.SetLibraryPath(libPath);
                SevenZipCompressor sevenZipCompressor = new SevenZipCompressor();
                sevenZipCompressor.CompressionLevel = CompressionLevel.Fast;
                sevenZipCompressor.ArchiveFormat = OutArchiveFormat.Zip;

                //被压缩对象是否存在
                int beforeObjectNameIndex = objectPathName.LastIndexOf('\\');
                string objectPath = objectPathName.Substring(, beforeObjectNameIndex);
                //System.IO.DirectoryInfo directoryInfo = new System.IO.DirectoryInfo(objectPathName);
                if (Directory.Exists(objectPathName)/*directoryInfo.Exists*/ == false && System.IO.File.Exists(objectPathName) == false)
                {
                    return CompressResults.SourceObjectNotExist;
                }
                int beforeObjectRarNameIndex = objectZipPathName.LastIndexOf('\\');
                int objectRarNameIndex = beforeObjectRarNameIndex + ;
                //string objectZipName = objectZipPathName.Substring(objectRarNameIndex);
                string objectZipPath = objectZipPathName.Substring(, beforeObjectRarNameIndex);
                //目标目录、文件是否存在
                if (Directory.Exists(objectZipPath) == false)
                {
                    Directory.CreateDirectory(objectZipPath);
                }
                else if (File.Exists(objectZipPathName) == true)
                {
                    File.Delete(objectZipPathName);
                }

                if (Directory.Exists(objectPathName))       //压缩对象是文件夹
                {
                    if (String.IsNullOrEmpty(strPassword))
                    {
                        sevenZipCompressor.CompressDirectory(objectPathName, objectZipPathName);
                    }
                    else
                    {
                        sevenZipCompressor.CompressDirectory(objectPathName, objectZipPathName, strPassword);
                    }
                }
                else        //压缩对象是文件 无加密方式
                {
                    sevenZipCompressor.CompressFiles(objectZipPathName, objectPathName);
                }

                return CompressResults.Success;
            }
            catch (Exception ex)
            {
                //throw new Exception(ex.Message) ;
                return CompressResults.UnKnown;
            }
        }

        /// <summary>
        /// 解压缩文件
        /// </summary>
        /// <param name="zipFilePathName">zip文件具体路径+名</param>
        /// <param name="unCompressDir">解压路径</param>
        /// <param name="strPassword">解密码</param>
        /// <returns></returns>
        public UnCompressResults UnCompress7zZip(String zipFilePathName, String unCompressDir, String strPassword)
        {
            try
            {
                //SevenZipSharp.dll、zLib1.dll、7z.dll必须同时存在，否则常报“加载7z.dll错误”而项目引用时，只引用SevenZipSharp.dll就可以了
                //string libPath = System.AppDomain.CurrentDomain.BaseDirectory + @"..\..\7z.dll";
                string libPath = "7z.dll";
                SevenZip.SevenZipCompressor.SetLibraryPath(libPath);

                bool isFileExist = File.Exists(zipFilePathName);
                if (false == isFileExist)
                {
                    //MessageBox.Show("解压文件不存在！" + zipFilePathName);
                    return UnCompressResults.SourceObjectNotExist;
                }
                File.SetAttributes(zipFilePathName, FileAttributes.Normal);     //去掉只读属性

                if (Directory.Exists(unCompressDir) == false)
                {
                    Directory.CreateDirectory(unCompressDir);
                }

                SevenZip.SevenZipExtractor sevenZipExtractor;
                if (String.IsNullOrEmpty(strPassword))
                {
                    sevenZipExtractor = new SevenZip.SevenZipExtractor(zipFilePathName);
                }
                else
                {
                    sevenZipExtractor = new SevenZip.SevenZipExtractor(zipFilePathName, strPassword);
                }

                sevenZipExtractor.ExtractArchive(unCompressDir);
                sevenZipExtractor.Dispose();
                return UnCompressResults.Success;
            }
            catch (Exception ex)
            {
                //MessageBox.Show("解压缩文件失败！" + ex.Message);
                return UnCompressResults.UnKnown;
            }
        }
        #endregion
    }

此方法需要引用sevenzipsharp.dll，同时在需要zlib1.dll和7z.dll两个库，这两个不需要引用，但是要跟sevenzipsharp.dll放在同一个文件夹下。

注：代码中

string libPath=... 要改为string libPath =“7z.dll“，或者为：”

string libPath =Path.Combine（System.AppDomain.CurrentDomain.BaseDirectory，“7z.dll”）；