The ASP.NET Web API has replaced the WCF Web API previously mentioned.
I thought I’d post an updated answer since most of these responses are from early 2012, and this thread is one of the top results when doing a Google search for “call restful service C#”.
Current guidance from Microsoft is to use the Microsoft ASP.NET Web API Client Libraries to consume a RESTful service. This is available as a NuGet package, Microsoft.AspNet.WebApi.Client. You will need to add this NuGet package to your solution.
Here’s how your example would look when implemented using the ASP.NET Web API Client Library:
using System;
using System.Collections.Generic;
using System.Net.Http;
using System.Net.Http.Headers;
namespace ConsoleProgram
{
public class DataObject
{
public string Name { get; set; }
}
public class Class1
{
private const string URL = "https://sub.domain.com/objects.json";
private string urlParameters = "?api_key=123";
static void Main(string[] args)
{
HttpClient client = new HttpClient();
client.BaseAddress = new Uri(URL);
// Add an Accept header for JSON format.
client.DefaultRequestHeaders.Accept.Add(
new MediaTypeWithQualityHeaderValue("application/json"));
// List data response.
HttpResponseMessage response = client.GetAsync(urlParameters).Result; // Blocking call! Program will wait here until a response is received or a timeout occurs.
if (response.IsSuccessStatusCode)
{
// Parse the response body.
var dataObjects = response.Content.ReadAsAsync<IEnumerable<DataObject>>().Result; //Make sure to add a reference to System.Net.Http.Formatting.dll
foreach (var d in dataObjects)
{
Console.WriteLine("{0}", d.Name);
}
}
else
{
Console.WriteLine("{0} ({1})", (int)response.StatusCode, response.ReasonPhrase);
}
// Make any other calls using HttpClient here.
// Dispose once all HttpClient calls are complete. This is not necessary if the containing object will be disposed of; for example in this case the HttpClient instance will be disposed automatically when the application terminates so the following call is superfluous.
client.Dispose();
}
}
}
If you plan on making multiple requests, you should re-use your HttpClient instance. See this question and its answers for more details on why a using statement was not used on the HttpClient instance in this case: Do HttpClient and HttpClientHandler have to be disposed between requests?
For more details, including other examples, see Call a Web API From a .NET Client (C#)
This blog post may also be useful: Using HttpClient to Consume ASP.NET Web API REST Services