Following code snippet shows how to get query string from a url using C#.
string urlString = "http://www.ezzylearning.com/Default.aspx?technology=Java&id=5&year=2015";
Uri uri = new Uri(urlString);
string queryString = uri.Query;
If you want to get the value of individual query string parameter then you can use following code snippet.
string technology = System.Web.HttpUtility.ParseQueryString(queryString).Get("technology");