我必须在asp.net webforms（c#）https://connect.mycomp.in/ConnectTP/PlaceOrder中调用一个rest API

Below is the curl example
curl \
-X POST https://BaseURL/PlaceOrder \
-d "jData={\"uid\":\"Test\", \"actid\":\"Test\", 
\"qty\":\"50\", \"price\":\"1400\", \"ret\":\"DAY\"}“ \
-d “jKey=TRELIU34533456SSUDFGU234”

我正在尝试使用JavaScriptSerializer，但它不能按预期工作，任何帮助都非常感谢。先谢谢你了

object input = new jData
                {
                    uid = "xxxxxxx",
                    actid = "xxxxxxx",
                    ..........,
                    ..........,
                 },jKey = "KEYHERe";
  string inputJson = (new JavaScriptSerializer()).Serialize(input);

--更新-
服务器返回了错误的请求，有人可以引导吗

var jd1 = new jData
        {
            uid = "xxxxxxx",
            actid = "xxxxxxx",
            ................,
            ..........,

        };

        object input = new PlaceOrderParam
        {
            jData = jd1,
            jKey = Session["tk"].ToString()
        };

        string inputJson = (new JavaScriptSerializer()).Serialize(input);
        WebClient client = new WebClient();
        client.Headers["Content-type"] = "application/json";
        client.Encoding = Encoding.Default;
        string json = client.UploadString(apiUrl, inputJson);

更新2----------------------------------------------------

using (var httpClient = new HttpClient())
            {
                using (var request = new HttpRequestMessage(new HttpMethod("POST"), apiUrl))
                {
                    request.Content = new StringContent("jData={\"uid\":\"xxxxxxx\",\"actid\":\"xxxxxxx\",\"ret\":\"DAY\"}\" , \"jKey=" + Session["tk"].ToString() + "");
                    request.Content.Headers.ContentType = MediaTypeHeaderValue.Parse("application/json");

                    var response =  await httpClient.SendAsync(request);
                }
            }

尝试将curl转换为HttpClient，但仍然是错误的请求
更新3--------------------

QUERY PARAMETERS
Parameter
Name    Possible value  Description
jData*      Should send json object with fields in below list
jKey*       Key Obtained on login success.