压缩部分：
         try
            {
                string Rarexe = @"C:\Program Files\WinRAR\WinRAR.exe"; 
                //WinRAR.exe 的完整路径
                string mulu = @"F:\仓存数据\";
                // 子文件所在目录
                string fileList =null;

                fileList += (mulu + "NewDB.xlsx ");

                fileList += (mulu + "出入库总表.xlsx ");

                fileList += (mulu + "A11-台账.xlsx ");

                fileList += (mulu + "A10-台账.xlsx ");

                fileList += (mulu + "A08-台账.xlsx ");

                fileList += (mulu + "A05-台账.xlsx ");
                // 组织压缩文件列表
                string Cmd = string.Format("a " + DateTime.Now.ToString() + " {0} -r -ibck -inul",fileList); 
                //WinRAR 命令参数 
                ProcessStartInfo Startinfo = new ProcessStartInfo();
                Startinfo.FileName = Rarexe;
                // 设置压缩主程序位置
                Startinfo.Arguments = Cmd;                          
                // 设置命令参数  
                Startinfo.WorkingDirectory = @"F:\仓存数据\备份\7\";
                // 文件保存路径
                Process Process = new Process();
                // 创建新进程
                Process.StartInfo = Startinfo;
                // 给进程传递所有参数
                Process.Start();
                // 启动进程
                Process.WaitForExit(); 
                // 无限期等待进程 winrar.exe 退出      
                Process.Close();
                // 释放所有占用的资源
                MessageBox.Show("压缩完成！");
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message);
            }

解压部分：
        try
            {
                string Rarexe = @"C:\Program Files\WinRAR\WinRAR.exe";
                //WinRAR.exe 的完整路径
                string jypath = @"C:\";
                // 解压存放的路径
                Directory.CreateDirectory(jypath);
                // 创建指定路径的文件夹
                string Cmd = string.Format("x {0} {1} -ibck -inul ", @"F:\仓存数据\2014-7-10.rar", jypath);
                //WinRAR 命令参数 
                ProcessStartInfo Startinfo = new ProcessStartInfo();
                Startinfo.FileName = Rarexe;
                // 设置压缩主程序位置
                Startinfo.Arguments = Cmd;
                // 设置命令参数  
                Process Process = new Process();
                // 创建新进程
                Process.StartInfo = Startinfo;
                // 给进程传递所有参数
                Process.Start();
                // 启动进程
                Process.WaitForExit();
                // 无限期等待进程 winrar.exe 退出      
                Process.Close();
                // 释放所有占用的资源
                MessageBox.Show("成功解压到：" + jypath);
            }
            catch (Exception em)
            {
                MessageBox.Show(em.Message);
            }

其他参数：

C# 文件压缩与解压