Csharp Articles - Page 27 of 259

Testing WebApi involves sending a request and receiving the response. There are several ways to test the WebApi. Here we will test the WebApi using postman and swagger. Let us create a StudentController like below.Student Modelnamespace DemoWebApplication.Models{    public class Student{       public int Id { get; set; }       public string Name { get; set; }    } }Student ControllerExampleusing DemoWebApplication.Models; using System.Collections.Generic; using System.Linq; using System.Web.Http; namespace DemoWebApplication.Controllers{    public class StudentController : ApiController{       List students = new List{          new Student{             ... Read More

HttpClient class provides a base class for sending/receiving the HTTP requests/responses from a URL. It is a supported async feature of .NET framework. HttpClient is able to process multiple concurrent requests. It is a layer over HttpWebRequest and HttpWebResponse. All methods with HttpClient are asynchronous. HttpClient is available in System.Net.Http namespace.Let us create an WebAPI application having a StudentController and respective action methods.Student Modelnamespace DemoWebApplication.Models{    public class Student{       public int Id { get; set; }       public string Name { get; set; }    } }Student Controllerusing DemoWebApplication.Models; using System.Collections.Generic; using System.Linq; using System.Web.Http; ... Read More

Authorization is the process of deciding whether the authenticated user is allowed to perform an action on a specific resource (Web API Resource) or not. For example, having the permission to get data and post data is a part of authorization. The Authorization Process happens before executing the Controller Action Method which provides you the flexibility to decide whether we want to grant access to that resource or not.In ASP.NET Web API authorization is implemented by using the Authorization filters which will be executed before the controller action method executed. Web API provides a built-in authorization filter, AuthorizeAttribute. This filter ... Read More

Content negotiation is the process of selecting the best representation for a given response when there are multiple representations available. Means, depending on the Accept header value in the request, the server sends the response. The primary mechanism for content negotiation in HTTP are these request headers −Accept − Which media types are acceptable for the response, such as "application/json, " "application/xml, " or a custom media type such as "application/vnd.example+xml"Accept-Charset − Which character sets are acceptable, such as UTF-8 or ISO 8859-1.Accept-Encoding − Which content encodings are acceptable, such as gzip.Accept-Language − The preferred natural language, such as "en-us".The ... Read More

Child Action is only accessible by a child request. It will not respond to the URL requests. If an attempt is made, a runtime error will be thrown stating - Child action is accessible only by a child request. Child action methods can be invoked by making child request from a view using Action() and RenderAction() html helpers.Child action methods are different from NonAction methods, in that NonAction methods cannot be invoked using Action() or RenderAction() helpers.Below is the Child Action Error when we try to invoke it using URL.ControllerExampleusing System.Collections.Generic; using System.Web.Mvc; namespace DemoMvcApplication.Controllers{    public class HomeController : ... Read More

In an ASP .Net MVC application filters can be applied in three levels.Action Method LevelController LevelGlobal LevelAction Method LevelFilters that are applied at the Action Method level will work only particularly for that action method.using System.Web.Mvc; namespace DemoMvcApplication.Controllers{    public class HomeController : Controller{       [Authorize] //Action Method Level       public string Index(){          return "Index Invoked";       }    } }Controller LevelController level filters are applied to all the action methods. The following filter are applicable to all the action methods of the HomeController, but not on other controllers.using System.Web.Mvc; ... Read More

The ASP.Net MVC Routing module is responsible for mapping incoming browser requests to particular MVC controller actions. When the ASP.NET MVC application launches then the application registers one or more patterns with the framework's route table to tell the routing engine what to do with any requests that matches those patterns. When the routing engine receives a request at runtime, it matches that request's URL against the URL patterns registered with it and gives the response according to a pattern match.ASP.NET introduced Routing to eliminate the needs of mapping each URL with a physical file. Routing enables us to define ... Read More

The NonAction attribute is used when we want a public method in a controller but do not want to treat it as an action method. An action method is a public method in a controller that can be invoked using a URL. So, by default, if we have any public method in a controller then it can be invoked using a URL request. To restrict access to public methods in a controller, NonAction attribute can be used.Now let us consider HomeController having two public methods MyMethod1 and MyMethod2.ControllerExampleusing System.Web.Mvc; namespace DemoMvcApplication.Controllers{    public class HomeController : Controller{       ... Read More

ViewBag uses the dynamic feature that was introduced in to C# 4.0. It allows an object to have properties dynamically added to it. Internally, it is a dynamic type property of the ControllerBase class which is the base class of the Controller class.ViewBag only transfers data from controller to view, not visa-versa. ViewBag values will be null if redirection occurs. ViewBag is able to set and get value dynamically and able to add any number of additional fields without converting it to strongly typed.Storing data in ViewBag −ViewBag.Counties = countriesList;Retrieving data from ViewBag −string country = ViewBag.Countries;ControllerExampleusing System.Collections.Generic; using System.Web.Mvc; ... Read More

A regular expression is a pattern that could be matched against an input text. The .Net framework provides a regular expression engine that allows such matching. A pattern consists of one or more character literals, operators, or constructs.Here are basic pattern metacharacters used by RegEx −* = zero or more ? = zero or one ^ = not [] = rangeThe ^ symbol is used to specify not condition.the [] brackets if we are to give range values such as 0 - 9 or a-z or A-ZUsing Char.IsDigit()Example Live Demousing System; namespace DemoApplication{    public class Program{       static ... Read More