C#: HttpClient with POST parameters

Question

I use codes below to send POST request to a server:

string url = "http://myserver/method?param1=1&param2=2"    
HttpClientHandler handler = new HttpClientHandler();
HttpClient httpClient = new HttpClient(handler);
HttpRequestMessage request = new HttpRequestMessage(HttpMethod.Post, url);
HttpResponseMessage response = await httpClient.SendAsync(request);

I don't have access to the server to debug but I want to know, is this request sent as POST or GET?

If it is GET, How can I change my code to send param1 & param2 as POST data (not in the URL)?

Answer 1

A cleaner alternative would be to use a Dictionary to handle parameters. They are key-value pairs after all.

private static readonly HttpClient httpclient;

static MyClassName()
{
    // HttpClient is intended to be instantiated once and re-used throughout the life of an application. 
    // Instantiating an HttpClient class for every request will exhaust the number of sockets available under heavy loads. 
    // This will result in SocketException errors.
    // https://docs.microsoft.com/en-us/dotnet/api/system.net.http.httpclient?view=netframework-4.7.1
    httpclient = new HttpClient();    
} 

var url = "http://myserver/method";
var parameters = new Dictionary<string, string> { { "param1", "1" }, { "param2", "2" } };
var encodedContent = new FormUrlEncodedContent (parameters);

var response = await httpclient.PostAsync (url, encodedContent).ConfigureAwait (false);
if (response.StatusCode == HttpStatusCode.OK) {
    // Do something with response. Example get content:
    // var responseContent = await response.Content.ReadAsStringAsync ().ConfigureAwait (false);
}

Also dont forget to Dispose() httpclient, if you dont use the keyword using

As stated in the Remarks section of the HttpClient class in the Microsoft docs, HttpClient should be instantiated once and re-used.

Edit:

You may want to look into response.EnsureSuccessStatusCode(); instead of if (response.StatusCode == HttpStatusCode.OK).

You may want to keep your httpclient and dont Dispose() it. See: Do HttpClient and HttpClientHandler have to be disposed?

Edit:

Do not worry about using .ConfigureAwait(false) in .NET Core. For more details look at https://blog.stephencleary.com/2017/03/aspnetcore-synchronization-context.html