Now a days JSON is the most popularly used data exchange format due to its simplicity and light weight, therefore we will see how to hit the API and then parse the received JSON in C#.

Please go through the following example:

public DataSet ApiCall(int categoryId)
        {
            DataSet ds = null;
            HttpClient client = new HttpClient();
            client.BaseAddress = new Uri(ConfigurationManager.AppSettings.Get("APIURL"));
            client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
            HttpResponseMessage response = client.GetAsync(string.Format("api/solar/GetSubCategories?CategoryId={0}", CategoryId)).Result;
            if (response.IsSuccessStatusCode)
            {
                var json = response.Content.ReadAsAsync<dynamic>().Result;
                ds = JsonConvert.DeserializeObject<DataSet>(json);
                return ds;               
            }
            return null;

        }

Note:-> These are the dlls to be referenced for parsing: System.Net.Http,System.Net.Http.Headers, Newtonsoft.Json;

    In this above example we are hitting the method GetSubCategories of an API and passing the parameter CategoryId in the URL. On recieving the successful responce from the API the responce is read into an object "json" by the code line

var json = response.Content.ReadAsAsync<dynamic>().Result;

This json object is then deserialized into DataSet object:

ds = JsonConvert.DeserializeObject<DataSet>(json);

Instead of taking dataset we can also create our own class as per the JSON . Following is a site where you can paste your JSON and you will get its corresponding class. JSON TO CLASS