我想使用 c# 从 Twitter api 获取电子邮件地址.我已经尝试过了，但它会引发一些异常

以下代码是我用C#编写的。谁能帮我？

public string  Verify_Credentials(string oauthconsumerkey, string oauthconsumersecret, string oauthtoken, string oauthtokensecret)
{
        string oauthsignaturemethod = "HMAC-SHA1";
        string oauthversion = "1.0";
        string oauthnonce = Convert.ToBase64String(new ASCIIEncoding().GetBytes(DateTime.Now.Ticks.ToString()));
        TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);
        string oauthtimestamp = Convert.ToInt64(ts.TotalSeconds).ToString();
        SortedDictionary<string, string> basestringParameters = new SortedDictionary<string, string>();
        basestringParameters.Add("oauth_version", "1.0");
        basestringParameters.Add("oauth_consumer_key", oauthconsumerkey);
        basestringParameters.Add("oauth_nonce", oauthnonce);
        basestringParameters.Add("oauth_signature_method", "HMAC-SHA1");
        basestringParameters.Add("oauth_timestamp", oauthtimestamp);
        basestringParameters.Add("oauth_token", oauthtoken);
        //GS - Build the signature string
        StringBuilder baseString = new StringBuilder();
        baseString.Append("GET" + "&");
        baseString.Append(EncodeCharacters(Uri.EscapeDataString("https://api.twitter.com/1.1/account/verify_credentials.json") + "&"));
        foreach (KeyValuePair<string, string> entry in basestringParameters)
        {
            baseString.Append(EncodeCharacters(Uri.EscapeDataString(entry.Key + "=" + entry.Value + "&")));
        }
        //Since the baseString is urlEncoded we have to remove the last 3 chars - %26
        string finalBaseString = baseString.ToString().Substring(0, baseString.Length - 3);
        //Build the signing key
        string signingKey = EncodeCharacters(Uri.EscapeDataString(oauthconsumersecret)) + "&" +
        EncodeCharacters(Uri.EscapeDataString(oauthtokensecret));
        //Sign the request
        HMACSHA1 hasher = new HMACSHA1(new ASCIIEncoding().GetBytes(signingKey));
        string oauthsignature = Convert.ToBase64String(hasher.ComputeHash(new ASCIIEncoding().GetBytes(finalBaseString)));
        string responseFromServer = string.Empty;
        //Tell Twitter we don't do the 100 continue thing
        ServicePointManager.Expect100Continue = false;
        //authorization header
        HttpWebRequest hwr = (HttpWebRequest)WebRequest.Create(
          @"https://api.twitter.com/1.1/account/verify_credentials.json?include_email=true");
        StringBuilder authorizationHeaderParams = new StringBuilder();
        authorizationHeaderParams.Append("OAuth ");
        authorizationHeaderParams.Append("include_email=" + "'"" + "true" + "'",");
        authorizationHeaderParams.Append("oauth_nonce=" + "'"" + Uri.EscapeDataString(oauthnonce) + "'",");
        authorizationHeaderParams.Append("oauth_signature_method=" + "'"" + Uri.EscapeDataString(oauthsignaturemethod) + "'",");
        authorizationHeaderParams.Append("oauth_timestamp=" + "'"" + Uri.EscapeDataString(oauthtimestamp) + "'",");
        authorizationHeaderParams.Append("oauth_consumer_key=" + "'"" + Uri.EscapeDataString(oauthconsumerkey) + "'",");
        if (!string.IsNullOrEmpty(oauthtoken))
            authorizationHeaderParams.Append("oauth_token=" + "'"" + Uri.EscapeDataString(oauthtoken) + "'",");
        authorizationHeaderParams.Append("oauth_signature=" + "'"" + Uri.EscapeDataString(oauthsignature) + "'",");
        authorizationHeaderParams.Append("oauth_version=" + "'"" + Uri.EscapeDataString(oauthversion) + "'"");
        hwr.Headers.Add("Authorization", authorizationHeaderParams.ToString());
        hwr.Method = "GET";
        hwr.ContentType = "application/x-www-form-urlencoded";
        //Allow us a reasonable timeout in case Twitter's busy
        hwr.Timeout = 3 * 60 * 1000;
        try
        {
          //  hwr.Proxy = new WebProxy("enter proxy details/address");
            HttpWebResponse rsp = hwr.GetResponse() as HttpWebResponse;
            Stream dataStream = rsp.GetResponseStream();
            //Open the stream using a StreamReader for easy access.
            StreamReader reader = new StreamReader(dataStream);
            //Read the content.
            responseFromServer = reader.ReadToEnd();
        }
        catch (Exception ex)
        {
        }
        return responseFromServer;
}
private string EncodeCharacters(string data)
    {
        //as per OAuth Core 1.0 Characters in the unreserved character set MUST NOT be encoded
        //unreserved = ALPHA, DIGIT, '-', '.', '_', '~'
        if (data.Contains("!"))
            data = data.Replace("!", "%21");
        if (data.Contains("'"))
            data = data.Replace("'", "%27");
        if (data.Contains("("))
            data = data.Replace("(", "%28");
        if (data.Contains(")"))
            data = data.Replace(")", "%29");
        if (data.Contains("*"))
            data = data.Replace("*", "%2A");
        if (data.Contains(","))
            data = data.Replace(",", "%2C");
        return data;
    }    

https://api.twitter.com/1.1/account/verify_credentials.json