HttpClient and how to use Headers, Content-Type and PostAsync

HttpClient.cs

// HttpClient and how to use Headers, Content-Type and PostAsync
// http://d-fens.ch/2014/04/12/httpclient-and-how-to-use-headers-content-type-and-postasync/

// Copyright 2014-2015 Ronald Rink, d-fens GmbH

// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

// http://www.apache.org/licenses/LICENSE-2.0

// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// NOTICE
// d-fens HttpClient
// this software contains work developed at
// d-fens GmbH, General-Guisan-Strasse 6, CH-6300 Zug, Switzerland

using System.Net.Http;
using System.Net.Http.Formatting;
using System.Net.Http.Headers;
//using System.Json;

string Invoke(
  string Method
  ,
  string Uri
  ,
  string Body
  )
{
  var cl = new HttpClient();
  cl.BaseAddress = new Uri(Uri);
  int _TimeoutSec = 90;
  cl.Timeout = new TimeSpan(0, 0, _TimeoutSec);
  string _ContentType = "application/json";
  cl.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(_ContentType));
  var _CredentialBase64 = "RWRnYXJTY2huaXR0ZW5maXR0aWNoOlJvY2taeno=";
  cl.DefaultRequestHeaders.Add("Authorization", String.Format("Basic {0}", _CredentialBase64));
  var _UserAgent = "d-fens HttpClient";
  // You can actually also set the User-Agent via a built-in property
  cl.DefaultRequestHeaders.Add("User-Agent", _UserAgent);
  // You get the following exception when trying to set the "Content-Type" header like this:
  // cl.DefaultRequestHeaders.Add("Content-Type", _ContentType);
  // "Misused header name. Make sure request headers are used with HttpRequestMessage, response headers with HttpResponseMessage, and content headers with HttpContent objects."

  HttpResponseMessage response;
  var _Method = new HttpMethod(Method);

  switch (_Method.ToString().ToUpper())
  {
    case "GET":
    case "HEAD":
      // synchronous request without the need for .ContinueWith() or await
      response = cl.GetAsync(Uri).Result;
      break;
    case "POST":
      {
        // Construct an HttpContent from a StringContent
        HttpContent _Body = new StringContent(Body);
        // and add the header to this object instance
        // optional: add a formatter option to it as well
        _Body.Headers.ContentType = new MediaTypeHeaderValue(_ContentType);
        // synchronous request without the need for .ContinueWith() or await
        response = cl.PostAsync(Uri, _Body).Result;
      }
      break;
    case "PUT":
      {
        // Construct an HttpContent from a StringContent
        HttpContent _Body = new StringContent(Body);
        // and add the header to this object instance
        // optional: add a formatter option to it as well
        _Body.Headers.ContentType = new MediaTypeHeaderValue(_ContentType);
        // synchronous request without the need for .ContinueWith() or await
        response = cl.PutAsync(Uri, _Body).Result;
      }
      break;
    case "DELETE":
      response = cl.DeleteAsync(Uri).Result;
      break;
    default:
      throw new NotImplementedException();
      break;
  }
  // either this - or check the status to retrieve more information
  response.EnsureSuccessStatusCode();
  // get the rest/content of the response in a synchronous way
  var content = response.Content.ReadAsStringAsync().Result;

  return content;
}

NOTICE

// d-fens HttpClient
// this software contains work developed at
// d-fens GmbH, General-Guisan-Strasse 6, CH-6300 Zug, Switzerland

Kindly help me to foodics POS Integration

following are my code it (Asp.net web api C#)

using (var client = new HttpClient())
{
var url = "https://dev-dash.foodics.com/api/v2/orders";
var cl = new HttpClient();
cl.BaseAddress = new Uri(url);
int _TimeoutSec = 90;
cl.Timeout = new TimeSpan(0, 0, _TimeoutSec);
string _ContentType = "application/json";
cl.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(_ContentType));
client.DefaultRequestHeaders.Add("Authorization", "Bearer " + obj.Token);
var response = await client.GetStringAsync(url);
}

a well organized article, adding (if required) "_Body.Headers.ContentMD5 = md5Hash" would do it more comprehensive, thanks...