400 - Bad Request Error while adding "fields" information to a jira transition using HttpClient and c#

Jira Development
,
1

I’m trying to transition a jira issue with content. At the moment I have this which works to transition the issue:

using (var httpClient = new HttpClient())
{
    using (var request = new HttpRequestMessage(new HttpMethod("POST"), restUrl))
    {
    string base64Credentials = GetEncodedCredentials();
    request.Headers.Authorization = new AuthenticationHeaderValue("Basic", base64Credentials);

    var requestBody = new
    {
        transition = new
         {
            id = "11"
         }
     };
}

var jsonRequestBody = Newtonsoft.Json.JsonConvert.SerializeObject(requestBody);
request.Content = new StringContent(jsonRequestBody);
request.Content.Headers.ContentType = new         MediaTypeHeaderValue("application/json");
var response = await httpClient.SendAsync(request);

But when I try to add a field when transitioning this issue I get an “Status Code 400 - Bad Request” error. This field does exist when I transition manually.

// returns status code 400 - bad request
var requestBodyFull = new
{
    transition = new
    {
    id = "11"
    },
        fields = new
   {
       customfield_18421 = "Yes",
   }
};

I’ve also tried:

var jsonRequestBody = Newtonsoft.Json.JsonConvert.SerializeObject(@"{""transition"": {""id"":""11""},""fields"":{""customfield_18421"":""Yes""}}");
request.Content = new StringContent(jsonRequestBody);

request.Content = new StringContent(@"{""transition"":{""id"":""11""},""fields"": 
   {""customfield_18421"":""Yes""}}", Encoding.UTF8, "application/json")