引用DLL  System.Net.Http    System.Net.Http.Formatting

引用命名空间  using System.Net;   using System.IO;

HttpWebRequest wReq = (HttpWebRequest)WebRequest.Create("http://localhost:8087/api/Test/TestAPI");

wReq.Method = "Post";

wReq.ContentType = "application/json";

byte[] data = Encoding.Default.GetBytes("{\"ModifyDate\": \"sample string 1\",\"TimeStamp\": 2,\"Sign\": \"sample string 3\"}");

wReq.ContentLength = data.Length;

Stream reqStream = wReq.GetRequestStream();

reqStream.Write(data, 0, data.Length);

reqStream.Close();

using (StreamReader sr = new StreamReader(wReq.GetResponse().GetResponseStream()))

{

string result = sr.ReadToEnd();

//result即返回值

}