.net 6 Download File Controller Free
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In an MVC app, the view only displays information. The controller handles and responds to user input and interaction. For example, the controller handles URL segments and query-string values, and passes these values to the model. The model might use these values to query the database. For example:
The MVC architectural pattern separates an app into three main groups of components: Models, Views, and Controllers. This pattern helps to achieve separation of concerns: The UI logic belongs in the view. Input logic belongs in the controller. Business logic belongs in the model. This separation helps manage complexity when building an app, because it enables work on one aspect of the implementation at a time without impacting the code of another. For example, you can work on the view code without depending on the business logic code.
When you browse to the app and don't supply any URL segments, it defaults to the "Home" controller and the "Index" method specified in the template line highlighted above. In the preceding URL segments:
The Welcome method runs and returns the string This is the Welcome action method.... For this URL, the controller is HelloWorld and Welcome is the action method. You haven't used the [Parameters] part of the URL yet.
This tutorial explores the topic of ASP.NET MVC controllers, controller actions, and action results. After you complete this tutorial, you will understand how controllers are used to control the way a visitor interacts with an ASP.NET MVC website.
MVC controllers are responsible for responding to requests made against an ASP.NET MVC website. Each browser request is mapped to a particular controller. For example, imagine that you enter the following URL into the address bar of your browser:
In this case, a controller named ProductController is invoked. The ProductController is responsible for generating the response to the browser request. For example, the controller might return a particular view back to the browser or the controller might redirect the user to another controller.
As you can see from Listing 1, a controller is just a class (a Visual Basic .NET or C# class). A controller is a class that derives from the base System.Web.Mvc.Controller class. Because a controller inherits from this base class, a controller inherits several useful methods for free (We discuss these methods in a moment).
A controller exposes controller actions. An action is a method on a controller that gets called when you enter a particular URL in your browser address bar. For example, imagine that you make a request for the following URL:
A controller action must be a public method of a controller class. C# methods, by default, are private methods. Realize that any public method that you add to a controller class is exposed as a controller action automatically (You must be careful about this since a controller action can be invoked by anyone in the universe simply by typing the right URL into a browser address bar).
There are some additional requirements that must be satisfied by a controller action. A method used as a controller action cannot be overloaded. Furthermore, a controller action cannot be a static method. Other than that, you can use just about any method as a controller action.
So, if you want to return a View to the browser, you call the View() method. If you want to redirect the user from one controller action to another, you call the RedirectToAction() method. For example, the Details() action in Listing 3 either displays a view or redirects the user to the Index() action depending on whether the Id parameter has a value.
If a controller action returns a result that is not an action result - for example, a date or an integer - then the result is wrapped in a ContentResult automatically. For example, when the Index() action of the WorkController in Listing 5 is invoked, the date is returned as a ContentResult automatically.
The purpose of this tutorial was to introduce you to the concepts of ASP.NET MVC controllers, controller actions, and controller action results. In the first section, you learned how to add new controllers to an ASP.NET MVC project. Next, you learned how public methods of a controller are exposed to the universe as controller actions. Finally, we discussed the different types of action results that can be returned from a controller action. In particular, we discussed how to return a ViewResult, RedirectToActionResult, and ContentResult from a controller action.
In ASP.NET MVC, every controller class name must end with a word "Controller". For example, the home page controller name must be HomeController, and for the student page, it must be the StudentController. Also, every controller class must be located in the Controller folder of the MVC folder structure.
Add Scaffold dialog contains different templates to create a new controller. We will learn about other templates later. For now, select "MVC 5 Controller - Empty" and click Add. It will open the Add Controller dialog, as shown below
As you can see above, the StudentController class is derived from the Controller class. Every controller in MVC must be derived from this abstract Controller class. This base Controller class contains helper methods that can be used for various purposes.
I am working with an ASP.NET and ReactJS project, and I cannot figure out why my controller isn't working, while the one premade in the template works fine. I have referenced guides, old projects, and tutorials and still just cannot see what I am doing incorrectly. When i go to the route "/project" in the URL field, i simply get a blank page of the website template. But when I go to "/weatherforecast", i see a page with JSON data (this is what I am expecting to see).
You can also apply the [Route] attribute on the controller level, capturing the action as a parameter. That route would then be applied on all actions in the controller, unless a specific [Route] has been defined on a specific action, overriding the default set on the controller.
With that said, if the gurus are gonna preach the almighty state of thin controller-hood, we first have to understand why a fat controller is a code smell, what thin really means, and why it benefits us.
To be honest, the above controller is pretty tame, but the thing about business logic in the controller is, it encourages even more as time goes on. On a pinch, you or the next developer that needs to add some feature along the same code path will stick it riiight there. As will the next, and the next, and the next.
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