地址一：http://sms.coreshop.cn:9999/sms.aspx

地址二：http://sms.corecms.net:9999/sms.aspx

如果服务器不支持解析，

将sms.coreshop.cn改为101.201.41.194

<?xml version="1.0" encoding="utf-8" ?>
   <returnsms>
   <returnstatus>status</returnstatus>
   <message>message</message> 
   <remainpoint> remainpoint</remainpoint>
   <taskID>taskID</taskID> 
   <successCounts>successCounts</successCounts>
</returnsms>

{"ReturnStatus":"success","Message":"ok","RemainPoint":0,"TaskID":0,"SuccessCounts":0}

public string send_sms()
{
	string str_userid = "ID";
	string str_account = "账号";
	string str_password = "密码";
	string str_content = "内容";
	string str_mobile = "手机号码";//130xxxxxxxx,131xxxxxxxx多个号码用英文半角‘,’分隔

	string param = string.Format(@"action=send&userid={0}&account={1}&password={2}&content={3}&mobile={4}", str_userid, str_account, str_password, str_content, str_mobile);
	string url = "http://sms.coreshop.cn:9999/sms.aspx";
	Response.Write(PostSend(url, param));//输出返回值
}

private string PostSend(string url, string postdate)
{
	HttpWebRequest myHttpWebRequest = (HttpWebRequest)WebRequest.Create(url);
	myHttpWebRequest.ContentType = "application/x-www-form-urlencoded;charset=UTF-8";
	myHttpWebRequest.Method = "POST";
	Stream myRequestStream = myHttpWebRequest.GetRequestStream();
	StreamWriter myStreamWriter = new StreamWriter(myRequestStream);
	myStreamWriter.Write(postdate);
	myStreamWriter.Flush();
	myStreamWriter.Close();
	myRequestStream.Close();

	HttpWebResponse myHttpWebResponse = (HttpWebResponse)myHttpWebRequest.GetResponse();
	Stream myResponseStream = myHttpWebResponse.GetResponseStream();
	StreamReader myStreamReader = new StreamReader(myResponseStream, Encoding.GetEncoding("utf-8"));
	String outdata = myStreamReader.ReadToEnd();
	myStreamReader.Close();
	myResponseStream.Close();
	return outdata;
}

string apiUrl = "http://sms.coreshop.cn:9999/sms.aspx";
string strUserid = "ID";
string strAccount = "账号";
string strPassword = "密码";
string strContent = "内容";
string strMobile = "手机号码";//130xxxxxxxx,131xxxxxxxx多个号码用英文半角‘,’分隔
string strRt = "json"; //返回值格式，默认为xml
string strSignature = "核心商城系统"; //签名

var outJson = await apiUrl.PostUrlEncodedAsync(new
{
    action = "send",
    userid = strUserid,
    account = strAccount,
    password = strPassword,
    mobile = strMobile,
    content = "【" + strSignature + "】" + strContent,
    rt = strRt
}).ReceiveJson();