解压一个rar文件

/// <summary> 
/// 解压缩一个 rar 文件。 
/// </summary> 
/// <param name="zipFileName">要解压的 zip 文件。</param> 
/// <param name="extractLocation">zip 文件的解压目录。</param> 
/// <param name="password">zip 文件的密码。</param> 
/// <param name="overWrite">是否覆盖已存在的文件。</param> 
public static void UnZip(string zipFileName, string extractLocation, string password, bool overWrite)
{
    #region 实现
    string myExtractLocation = extractLocation;
    if (myExtractLocation == "")
    {
        myExtractLocation = Directory.GetCurrentDirectory();
    }
    if (!myExtractLocation.EndsWith("\\"))
    {
        myExtractLocation = myExtractLocation + "\\";
    }
    ZipInputStream s = new ZipInputStream(File.OpenRead(zipFileName));
    s.Password = password;
    ZipEntry theEntry;

    while ((theEntry = s.GetNextEntry()) != null)
    {
        string directoryName = "";
        string pathToZip = "";
        pathToZip = theEntry.Name;

        if (pathToZip != "")
            directoryName = Path.GetDirectoryName(pathToZip) + "\\";
        string fileName = Path.GetFileName(pathToZip);
        Directory.CreateDirectory(myExtractLocation + directoryName);
        if (fileName != "")
        {
            if ((File.Exists(myExtractLocation + directoryName + fileName) && overWrite) ||
            (!File.Exists(myExtractLocation + directoryName + fileName)))
            {
                FileStream streamWriter = File.Create(myExtractLocation + directoryName + fileName);
                int size = 2048;
                byte[] data = new byte[2048];
                while (true)
                {
                    size = s.Read(data, 0, data.Length);
                    if (size > 0)
                        streamWriter.Write(data, 0, size);
                    else
                        break;
                }
                streamWriter.Close();
            }
        }
    }
    s.Close();
    #endregion
    File.Delete(zipFileName);
}