46elksExample.cs

using System;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Collections.Generic;
using System.Threading.Tasks;

namespace elktest {
	class Program {

		public static string user = "<API Username>";
		public static string pwd = "<API Password>";
		private static HttpClient client;
		static void Main(string[] args)

		{
			Task.Run(async() = > {
				using(client = new HttpClient()) {
					client.BaseAddress = new Uri("https://api.46elks.com");

					client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(
						"Basic",
						Convert.ToBase64String(
							System.Text.ASCIIEncoding.ASCII.GetBytes(
								string.Format("{0}:{1}", user, pwd))));

					var content = new FormUrlEncodedContent(new[] {
						new KeyValuePair < string, string > ("from", "+46723175800"),
						new KeyValuePair < string, string > ("to", "+46735417172"),
						new KeyValuePair < string, string > ("message", "Test 😊"),
					});

					HttpResponseMessage response = await client.PostAsync("/a1/SMS", content);
					response.EnsureSuccessStatusCode();
					var result = await response.Content.ReadAsStringAsync();
				}
			}).Wait();
		}
	}
}