关于Microsoft.Exchange.WebServices.Data.ExchangeService的错误，请大神指教

Question

public static ExchangeService GetExchangeService()
    {
        DataTable dt = ReadConfigXml("~/app_data/email.xml");
        string userName = ReadConfigValue(dt, "ews_username").ToString();
        string password = ReadConfigValue(dt, "ews_password").ToString();
        string domain = ReadConfigValue(dt, "ews_domain").ToString();
        string uriString = ReadConfigValue(dt, "ews_exchangewebservice").ToString();
        string str5 = ReadConfigValue(dt, "ews_exchangeversion").ToString();
        ReadConfigValue(dt, "ews_mail").ToString();
        ExchangeService service = new ExchangeService();
        if (str5 != "")
        {
            switch (str5)
            {
                case "Exchange2007_SP1":
                    service = new ExchangeService(0);
                    goto Label_0169;                case "Exchange2010":
                    service = new ExchangeService(1);
                    goto Label_0169;                case "Exchange2010_SP1":
                    service = new ExchangeService(2);
                    goto Label_0169;                case "Exchange2010_SP2":
                    service = new ExchangeService(3);
                    goto Label_0169;                case "Exchange2013":
                    service = new ExchangeService(4);
                    goto Label_0169;                case "Exchange2013_SP1":
                    service = new ExchangeService(5);
                    goto Label_0169;
            }
            service = new ExchangeService();
        }
    Label_0169:
        ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(Helper.RemoteCertificateValidate);
        if (domain == "")
        {
            service.set_Credentials((ExchangeCredentials) new NetworkCredential(userName, password));
        }
        else
        {
            service.set_Credentials((ExchangeCredentials) new NetworkCredential(userName, password, domain));
        }
        service.set_Url(new Uri(uriString));
        service.set_Timeout(0x30d40);
        return service;
    }提示错误为：

Answer 1

你自己查 TimeZoneInfo 中什么枚举为 0 呗。反编译只是提示一下给你看，仅仅对最低级的最简单的代码的反编译才跟源代码相同，你还真把反编译它的代码当真啊？

Answer 2

因为switch-case-goto的写法
一般都是反编译出来的。你这个错误是new ExchangeService(4)初始化的时候有问题，
不能写整型数字int，需要具体的枚举类型

Answer 3

除了new ExchangeService(1)就开始出错了。
如果是编译前的写法，应该怎么写呀，网上查找的话，我应该怎么查找。
我是啥都不懂

Answer 4

除了new ExchangeService(1)就开始出错了。
如果是编译前的写法，应该怎么写呀，网上查找的话，我应该怎么查找。
我是啥都不懂
类ExchangeService的构造函数应该是可以传入一个枚举值的，
实例化的时候不要传入int，改成实际的枚举值