c#发送请求访问外部接口的实例

我就废话不多说了，大家还是直接看代码吧~

 string url = "https://cloud.soei.com.cn/smsapi/sms/verifycode";
   httpclient httpclient = new httpclient();
   httpclient.baseaddress = new uri(url);
   //表头参数
   string token = "9c0025b4aae442bda5498971ec1ab219";
   httpclient.defaultrequestheaders.add("token", token);
   httpclient.defaultrequestheaders.accept.clear();
   httpclient.defaultrequestheaders.accept.add(new mediatypewithqualityheadervalue("application/json"));
   try
   {
    using (var request = new httprequestmessage())
    {
     var postbody = $"{{\"identity\":\"{identity}\",\"phonenumber\":\"{phonenumber}\",\"code\":\"[code]\"}}";
     request.method = httpmethod.post;
     request.content = new stringcontent(postbody, encoding.utf8, "application/json");
     var response = await httpclient.sendasync(request);
     //返回结果
     var retstring = await response.content.readasstringasync();
     jobject items = (jobject)jsonconvert.deserializeobject(retstring);
     //返回码，成功为200
     string retcode = items["code"].tostring();
     返回消息
     string message = items["message"].tostring();
     string data = items["data"].tostring();
     jobject items_data = (jobject)jsonconvert.deserializeobject(data);
     string issuccess = items_data["issuccess"].tostring();
     string data_message = items_data["message"].tostring();
     if (issuccess == "false")
     {
      retcode = "300";
     }
     retmessage.retcode = retcode;
     retmessage.message = data_message;
    }
   }
   catch (exception e)
   {
    retmessage.retcode = "300";
    retmessage.message = e.message.tostring();
   }
 
   return retmessage;
  }

 public static async task<string> postdata(string path,string serverpath,dynamic param) {
   try
   {
    httpclient client = new httpclient();
   
    client.defaultrequestheaders.add("referer", string.format("http://{0}", serverpath));
    httpresponsemessage response;
    using (httpcontent httpcontent = new stringcontent(param, encoding.utf8))
    { 
     
     httpcontent.headers.contenttype = new system.net.http.headers.mediatypeheadervalue("application/json");
     //client.defaultrequestheaders.add("x-token", "m3q_mqewmn9l4ly7fm7dxamsdlyssup5lfklztf_vp97urf");
     response = await client.postasync(path, httpcontent).continuewith(res =>
     {
 
      return res;
 
     }).result;
    }
    if (response != null && response.issuccessstatuscode)
    {
     return await response.content.readasstringasync();
 
    }
    else
    {
     return string.empty;
    }
   }
   catch (exception ex)
   {
 
    throw;
   }
   finally
   {
   }
  }

补充：c#后台调用http外网接口（get, post）

1.get方法调用接口获取json文件内容

public void getfunction()
  {   
   string serviceaddress = "http://222.111.999.444:8687/tttr/usercrd/12/b7e50cb45a?userid=9999";
   httpwebrequest request = (httpwebrequest)webrequest.create(serviceaddress);
   request.method = "get";
   request.contenttype = "text/html;charset=utf-8";
   httpwebresponse response = (httpwebresponse)request.getresponse();
   stream myresponsestream = response.getresponsestream();
   streamreader mystreamreader = new streamreader(myresponsestream, encoding.utf8);
   string retstring = mystreamreader.readtoend();
   mystreamreader.close();
   myresponsestream.close();
   response.write(retstring);
  }

这个太复杂了 突然发现个简单的：

using (var client = new webclient()){
 client.encoding = encoding.utf8;
 string serviceaddress = urlappend + "cloud/device/data/geterrordata?appid=" + appid + "&accesstoken=" + accesstoken + "&timestamp=" + time + "&deviceids=" + deviceids;
  var data = client.downloadstring(serviceaddress);
  var obj = jsonconvert.deserializeobject<jobject>(data);
}
//obj就是返回数据的对象

2.post方法调用接口获取json文件内容

public void postfunction()
  {
   string serviceaddress = "http://222.111.999.444:8687/tttr/usercrd/uuu/12/dfd7e4";
   httpwebrequest request = (httpwebrequest)webrequest.create(serviceaddress);
   request.method = "post";
   request.contenttype = "application/json";
   string strcontent = @"{ ""mmmm"": ""89e"",""nnnnnn"": ""0101943"",""kkkkkkk"": ""e8sodijf9""}";
   using (streamwriter datastream = new streamwriter(request.getrequeststream()))
   {
    datastream.write(strcontent);
    datastream.close();
   }
   httpwebresponse response = (httpwebresponse)request.getresponse();
   string encoding = response.contentencoding;
   if (encoding == null || encoding.length < 1)
   {
    encoding = "utf-8"; //默认编码 
   }
   streamreader reader = new streamreader(response.getresponsestream(), encoding.getencoding(encoding));
   string retstring = reader.readtoend();
   //解析josn
   jobject jo = jobject.parse(retstring);
   response.write(jo["message"]["mmmm"].tostring());   
  } 

以上为个人经验，希望能给大家一个参考，也希望大家多多支持。如有错误或未考虑完全的地方，望不吝赐教。