使用ASP.NET MVC 3

publicActionResult About()
{
	return View("Index");
}

ViewBag is a dynamic object, where we can add any properties dynamically.

For example, if I want to pass some contact information like Name and Contact number to About View from the Home controller, we can define it using the ViewBag as:

This data will be accessed in about.cshtml as:

@{    
   ViewBag.Title = "About Us";
}
<h2About</h2
<divContact person : @ViewBag.ContactPerson 
      Contact Number : @ViewBag.Contactnumber</div>

namespaceSampleApp.Models
{public classContactAddress   
    {public string Address { getset; }public string City { get; <br />set; }public string Country { getset; }
    }
}

Now, let us construct the Model in Controller and pass the same to our View:

publicActionResult About()
{var address = new ContactAddress()
    {
        Address = "Lane 21, Gachibowli",
        City = "Hyderabad",
        Country = "India"};return View(address);
}

Now, we will use the same in our View. In View, we have another object called Model, which holds the dynamic properties like ViewBag. We can extract the model properties using Model.

@{
    ViewBag.Title = "About Us";
}
<h2>About</h2>
<div>
  Contact Address: @Model.Address, @Model.City, @Model.Country
</div>

public class SampleController : Controller
{
    //
    // GET: /Sample/
 
    public ActionResult Verify()
    {
        return View();
    }
}

public static void RegisterRoutes(RouteCollection routes)
{
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

    routes.MapRoute(
                "sample",
                "Sample/{action}",
                new { controller = "Sample", action = "Verify" }
                );

 
    routes.MapRoute(
                "Default", // Route name
                "{controller}/{action}/{id}", // URL with parameters
                new { controller = "Home", action = "Index", 
                      id = UrlParameter.Optional } // Parameter defaults
            );

}

routes.MapRoute(
                "sample",
                "Sample/{username}",
                new { controller = "Sample", action = "Verify" }
                );

routes.MapRoute(
                "sample",
                "Sample/{username}",
                new { controller = "Sample", action = "Verify", 
                      username=UrlParameter.Optional }
                );

Inside the Controller, specify the default value for the parameter.

public ActionResult Verify(string username="all")
{
    return Content(username);
}

When we need to return any text from a Controller action, we will use the Content type.

public ActionResult Index()
{
    return Content("Hello from Home Controller");
}

Depending on the input values, we can redirect to another Action. For redirecting to another Action, we will use the RedirectToAction type.

public ActionResult Index()
{
    // Redirect to Verify action inside the Sample Controller
    return RedirectToAction("Verify", "Sample");
}

When we need to redirect to a route defined in Global.asax, we will use the RedirectToRoute object.

As part of our sample application, we have a custom route defined with the name “sample”. This will route to the Index action inside the Sample Controller. For more on Custom routes, please refer to Controllers and Routers in ASP.NET MVC 3.

public ActionResult Index()
{
    return RedirectToRoute("sample");
}

File is used to return the content of a file to the browser. For our sample, I am returning the web.config to the browser.

public ActionResult Index()
{
    return File("Web.config", "text/html");
}

public ActionResult Index()
{
    return Json("hello from JSON","text/html", JsonRequestBehavior.AllowGet);
}

As we specified the type of the content, it will render to the browser as shown below:

public ActionResult Index()
{
    return Json("hello from JSON", JsonRequestBehavior.AllowGet);
}

Authorize filters ensure that the corresponding Action will be called by an authorized user only. If the user is not authorized, he will be redirected to the login page.

[Authorize]
public ActionResult About()
{
    return View();
}

[Authorize]
public class SampleController : Controller
{
    ……………………………………………
}

public ActionResult Index()
{
    throw new Exception("Verify the HandleError filter");
    ViewBag.Message = "Welcome to ASP.NET MVC!";
    return View();
}

ASP.NET MVC defines Action filters like OutputCache, ValidateInput, etc., as part of ASP.NET MVC 3, which we will discuss later.