MailChimp API add contact to list

MailChimpApiListAddContact.cs

// mailchimp API add member to list
// http://developer.mailchimp.com/documentation/mailchimp/reference/lists/members/

// how to get my Id List
// https://kb.mailchimp.com/lists/manage-contacts/find-your-list-id

var listId = "myListId";
var url = "https://us3.api.mailchimp.com/3.0/lists/" + listId + "/members";

using (HttpClient client = new HttpClient())
{
	client.DefaultRequestHeaders.Accept.Clear();
	client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
	client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", apiKey);

	// Serialize our concrete class into a JSON String
	
	// ADD multiple emails
	//var stringPayload = "{\"members\": [{\"email_address\": \"myemail@server.com\", \"status\": \"subscribed\", \"language\": \"pt_PT\"}], \"update_existing\": true}";
  
	// ADD one email
	var stringPayload = "{\"email_address\":\"myemail@server.com\", \"status\":\"subscribed\", \"language\": \"pt_PT\"}";

	// Wrap our JSON inside a StringContent which then can be used by the HttpClient class
	var httpContent = new StringContent(stringPayload, Encoding.UTF8, "application/json");

	try
	{
		HttpResponseMessage response = client.PostAsync(url, httpContent).Result;

		if (response.IsSuccessStatusCode)
		{

			var results = response.Content.ReadAsStringAsync().Result;

			<div>@results</div>
		}
		else
		{

			<div>error code : @response.StatusCode</div>
			<div>error : @response</div>
			<div>error Headers : @response.Headers</div>
			<div>error Content : @response.Content.ReadAsStringAsync().Result</div>

			//Console.WriteLine($"ERROR (HTTP Status = {response.StatusCode}");
		}


	}
	catch (HttpRequestException e)
	{
		<div>EXCEPTION: @e</div>
		// Handle exception.
	}
	catch (Exception e)
	{
		<div>EXCEPTION: @e.Message</div>
		//Console.WriteLine(e.Message);
	}
}