Cannot sent Post multipart/form-data Httpclient c# API

Question

I am trying to send by converting string feed XML to stream multipart/form-data but getting bad request as response. Please suggest correct way to post multipart/form-data as XML or text file data

 

sample code:

public async Task<string> PostAPICall(string feed,string clientID, string clientSecret)
{
try
{
HttpClient client = new HttpClient();
string uri = Constants.ApiUrl + "v3/feeds?feedType=item&setupType=byMatch";
string token = await _authentication.GetToken(clientID, clientSecret);
client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", Convert.ToBase64String(Encoding.ASCII.GetBytes(clientID + ":" + clientSecret)));
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
client.DefaultRequestHeaders.Add("WM_SEC.ACCESS_TOKEN", token );
client.DefaultRequestHeaders.Add("WM_SVC.NAME", "XXXXXXXXX");
client.DefaultRequestHeaders.Add("WM_QOS.CORRELATION_ID", System.Guid.NewGuid().ToString()); //any random ID
client.DefaultRequestHeaders.Add("WM_SVC.VERSION", "1.0.0");
HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, uri);
MultipartFormDataContent form = new MultipartFormDataContent();
HttpContent content = new StringContent("fileToUpload");
form.Add(content, "fileToUpload");
/*convert string to stream*/
byte[] byteArray = Encoding.ASCII.GetBytes(feed);
MemoryStream stream = new MemoryStream(byteArray);
content = new StreamContent(stream);
content.Headers.ContentDisposition = new ContentDispositionHeaderValue("form-data")
{
Name = "feeds",
FileName = "feeds.xml"
};
form.Add(content);
string result = string.Empty;
var response = client.PostAsync(uri, form).Result;
if (response.StatusCode == System.Net.HttpStatusCode.OK)
{
result = await response.Content.ReadAsStringAsync();
}
return result;
}
catch (Exception e)
{
throw e;
}
}