Invoke a POST method with XML Request message in C#

To invoke a POST method located at a particular URL with an XML request message, we need to follow the below steps:

1. Create a request to the url
2. Put required request headers
3. Convert the request XML message to a stream (or bytes)
4. Write the stream of bytes (our request xml) to the request stream
5. Get the response and read the response as a string

So, the code for the above steps looks something like this:

string xmlMessage = "<?xml version=\"1.0\" encoding=\"utf-8\" ?>\r\n" +
    "construct your xml request message as required by that method along with parameters";
    string url = "http://XXXX.YYYY/ZZZZ/ABCD.aspx";
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);

    byte[] requestInFormOfBytes = System.Text.Encoding.ASCII.GetBytes(xmlMessage);
    request.Method = "POST";
    request.ContentType = "text/xml;charset=utf-8";
    request.ContentLength = requestInFormOfBytes.Length;
    Stream requestStream = request.GetRequestStream();
    requestStream.Write(requestBytes, 0, requestInFormOfBytes.Length);
    requestStream.Close();

    HttpWebResponse response = (HttpWebResponse)request.GetResponse();
    StreamReader respStream = new StreamReader(response.GetResponseStream(), System.Text.Encoding.Default);
    string receivedResponse = respStream.ReadToEnd();
    Console.WriteLine(receivedResponse);
    respStream.Close();
    response.Close();

If the xmlMessage is formed correctly, then you should be getting the expected response from the web method located at the URL.

Hope this helps!