Для работы с SOAP API в Visual Studio есть ServiceReference
Для работы с REST API RestClient. У меня на гите есть пример его использования
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;
namespace VkSdk
{
public enum HttpVerb
{
GET,
POST,
PUT,
DELETE
}
public class RestClient
{
#region CONSTRUCTOR
public string EndPoint { get; set; }
public HttpVerb Method { get; set; }
public string ContentType { get; set; }
public string PostData { get; set; }
public RestClient()
{
EndPoint = "";
Method = HttpVerb.GET;
ContentType = "text/xml";
PostData = "";
}
public RestClient(string endpoint)
{
EndPoint = endpoint;
Method = HttpVerb.GET;
ContentType = "text/xml";
PostData = "";
}
public RestClient(string endpoint, HttpVerb method)
{
EndPoint = endpoint;
Method = method;
ContentType = "text/xml";
PostData = "";
}
public RestClient(string endpoint, HttpVerb method, string postData)
{
EndPoint = endpoint;
Method = method;
ContentType = "text/xml";
PostData = postData;
}
#endregion
public string MakeRequest()
{
return MakeRequest("");
}
public string MakeRequest(string parameters)
{
var request = (HttpWebRequest)WebRequest.Create(EndPoint + parameters);
request.Method = Method.ToString();
request.ContentLength = 0;
request.ContentType = ContentType;
if (!string.IsNullOrEmpty(PostData) && Method == HttpVerb.POST)
{
var encoding = new UTF8Encoding();
var bytes = Encoding.GetEncoding("iso-8859-1").GetBytes(PostData);
request.ContentLength = bytes.Length;
using (var writeStream = request.GetRequestStream())
{
writeStream.Write(bytes, 0, bytes.Length);
}
}
using (var response = (HttpWebResponse)request.GetResponse())
{
var responseValue = string.Empty;
if (response.StatusCode != HttpStatusCode.OK)
{
var message = String.Format("Request failed. Received HTTP {0}", response.StatusCode);
throw new ApplicationException(message);
}
// grab the response
using (var responseStream = response.GetResponseStream())
{
if (responseStream != null)
using (var reader = new StreamReader(responseStream))
{
responseValue = reader.ReadToEnd();
}
}
return responseValue;
}
}
}
}