What are Differences in Asp.net MVC 3, MVC 4 and MVC 5

Here are few differences:

• Razor view engine: ASP.NET MVC3 uses the ASPX view engine by default, while MVC4 and MVC5 introduced the Razor view engine, which is more concise and easier to read.

• Bundling and Minification: MVC4 introduced the new feature of bundling and minification, which makes it easier to combine and compress JavaScript and CSS files into a single file.

• Authentication filters: MVC5 introduced authentication filters that enable developers to apply authentication logic to controller actions or methods. This feature makes it easier to implement authentication logic in a modular and reusable way.

• Attribute routing: MVC5 introduced attribute routing, which provides a more intuitive and flexible way to define the URL routing rules. With attribute routing, you can define the route directly in the controller or action method, rather than in a central location.

• One ASP.NET: MVC5 introduced the concept of "One ASP.NET," which is a unified development model for web applications. It integrates ASP.NET MVC, Web API, and Web Pages into a single framework, making it easier to develop and maintain web applications.

• Bootstrap: MVC5 introduced support for Bootstrap, which is a popular front-end framework for building responsive web applications. With Bootstrap, you can quickly and easily create a modern and professional-looking user interface for your application.

• Filter overrides: MVC5 allows developers to override the filters defined in the global filter collection for a specific controller or action method. This feature makes it easier to customize the behavior of filters for specific parts of the application.

Overall, each version of ASP.NET MVC introduced new features and improvements that made it easier to develop web applications. As such, the latest version, MVC5, is generally the best choice for new projects, as it offers the most up-to-date feature

What are Action Filters in Asp.net MVC

In ASP.NET MVC, action filters are attributes that can be applied to controller actions or the entire controller itself to modify or enhance the behavior of the action method during its execution. They are used to inject additional processing logic before, during, or after the execution of the controller action.

Action filters can be used for a variety of purposes, such as authentication, authorization, caching, logging, exception handling, and more. They provide a way to intercept the execution of a controller action and add custom logic to it.

there are four types of action filters:

Authorization filters

These filters are used to authenticate the user and check if the user has the required permissions to access a particular action method or controller.

Action filters

These filters are used to execute code before and after an action method is called. They can be used to modify the action method's input or output, perform validation, or add or modify response headers.

Result filters

These filters are used to modify the result of an action method before it is returned to the client. They can be used to modify the response status code, add or modify response headers, or transform the response body.

Exception filters

These filters are used to handle exceptions that occur during the execution of an action method. They can be used to log the exception, modify the response, or redirect the user to an error page.

Action filters can be applied at the controller level or the action level. They can also be applied globally to all controllers and actions using the MVC middleware.

What are Advantages of Dotnet MVC

ASP.NET MVC (Model-View-Controller) is a web development framework that provides a number of advantages over traditional web forms development. 

Here are some advantages of using ASP.NET MVC:

Separation of concerns: 

The MVC pattern allows for a clear separation of concerns between the application's presentation logic, business logic, and data access logic. This makes it easier to maintain and modify the application code over time.

Testability: 

The separation of concerns provided by the MVC pattern also makes it easier to write unit tests for the application. Each component of the MVC pattern can be tested separately, which makes it easier to identify and fix bugs.

Flexibility: 

ASP.NET MVC provides developers with a high degree of flexibility in terms of how they structure their application code. This allows developers to create applications that meet the specific needs of their business requirements.

Performance: 

ASP.NET MVC applications are generally faster and more lightweight than traditional web forms applications. This is because MVC applications don't require the view state or server-side controls that web forms applications do.

SEO-friendly URLs: 

ASP.NET MVC provides built-in support for creating SEO-friendly URLs, which can help improve the search engine rankings of the application.

Support for modern web development techniques: 

ASP.NET MVC provides built-in support for modern web development techniques such as AJAX, JSON, and RESTful web services.

Overall, ASP.NET MVC is a powerful and flexible web development framework that provides developers with a number of advantages over traditional web forms development. It is well-suited for building modern, scalable, and maintainable web applications.