Asp.Net Get请求如何将参数放入信息体body中

using System.Net;
using System.IO;
using System.Reflection;
namespace Test.Controllers
{
    public class HomeController : Controller
    {
        public ActionResult test() {
            var request = WebRequest.Create("http://www.w3dev.cn");
            request.ContentType = "application/json";
            request.Method = "GET";
            request.ServicePoint.Expect100Continue = false;//取消Expect:100-continue请求头，要不服务器没有正确处理会报错，如IIS。远程服务器返回错误: (417) Expectation Failed。
            var type = request.GetType();
            var currentMethod = type.GetProperty("CurrentMethod", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(request);
            var methodType = currentMethod.GetType();
            methodType.GetField("ContentBodyNotAllowed", BindingFlags.NonPublic | BindingFlags.Instance).SetValue(currentMethod, false);
            using (var streamWriter = new StreamWriter(request.GetRequestStream()))
            {
                streamWriter.Write("{fid:123}");
            }
            var response = (HttpWebResponse)request.GetResponse();
            return Content("");
        }
}