C# Pass Json to HTTP Post Request

Question

I'm trying to pass in a Json String as a parameter for a HttpWebRequest along with a URL. The request will hit the methods fine, but every time the parameters are null. I've tried to follow many examples like this one, but with no success: How to send json data in POST request using C#

Here is the sample object that will be serialized and passed

Amount amount = new Amount
{
    currencyCode = "EUR",
    amount = 1234
}
string JsonParameters = amount.ToJson();
var result = Methods.ExecuteHttpPostRequestWithJson("http://localhost:51581/Home/Test", JsonParameters);

Json Parameters serializes correctly into

{"currencyCode":"EUR","amount":1234}

Here is the method I'm try to create. I've tried multiple ways but they end up being null each time.

Here is the method that will be called

public static string ExecuteHttpPostRequestWithJson(string URL, string Json)
    {
        string result = "";
        var httpWebRequest = (HttpWebRequest)WebRequest.Create(URL);
        httpWebRequest.ContentType = "application/json";
        httpWebRequest.Method = "POST";
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;

        using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
        {;
            streamWriter.Write(Json);
            streamWriter.Flush();
            streamWriter.Close();
        }

        var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
        using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
        {
            result = streamReader.ReadToEnd();
        }

        return result;
    }

Here is the method that gets correctly hit, but with null parameters for both currencyCode and amount.

[HttpPost]
public JsonResult Test(string currencyCode, string amount)
{
    return Json(new
    {
        Test = "It worked"
    });
}

you are creating an object in javascript. try creating a class in c# with currencyCode and amount and use the object of that class as parameter in your function — Nouman Bhatti, May 07 '18 at 23:29

egnomerator · Accepted Answer · 2018-05-08T00:27:01.570

1

In addition to what was suggested in the comment by Nouman Bhatti -- defining the amount class in your service as well as updating your service's POST method signature to expect that object -- also use the [FromBody] attribute

class

new Amount
{
    currencyCode = "EUR",
    amount = 1234
}

New POST method signature

[HttpPost]
public JsonResult Test([FromBody]Amount amount)

edited May 08 '18 at 00:27

answered May 08 '18 at 00:20

egnomerator

985
8
15

1

That was the solution! I've tried changing it to Amount before, but never did the [FromBody]. Thanks! – user3454910 May 08 '18 at 00:35

C# Pass Json to HTTP Post Request

1 Answers1