MVC and Razor Pages
Razor Pages are built into ASP.NET Core MVC and use the same features for routing, model binding, filters, authorization, etc.
Comparison:
| Technology | Organization | Routing | Request Handling |
|---|---|---|---|
| MVC | Separate folders for Controllers, Models, Views, etc. | Attribute-based routing | Controller Actions |
| Razor Pages | A single folder (/Pages) | Route based relative to location in folder | Handlers |
In Visual Studio:
| Project template | Uses | Missing | Use for |
|---|---|---|---|
| Web API | MVC controllers | /Views, /Pages — can be added | Web APIs |
| Web App | Razor Pages | /Views, /Pages — can be added | Web apps |
Razor Pages
The default approach for new web apps in Visual Studio. Razor Pages encapsulates server-side logic for a given logical “page” in a web application.
A Razor Page’s page model combines responsibilities of an MVC controller and a viewmodel. Instead of handling requests with controller actions, page model handlers like OnGet() are executed and render their associated page.
Mapping Requests to Responses
Concepts:
- Conventional routes (applied in middleware pipeline)
- Attribute routes (applied to controllers and actions)
- Content negotiation allows requests to specify how responses should be formatted (JSON, XML, etc)
When a request is matched to a route, but before the action is called, ASP.NET Core MVC will perform model binding and model validation on the request.
- Model binding converts incoming HTTP data into .NET types specified as parameters of the action method to be called.
- If the action method expects an int id, model binding will look for values in the route itself, query strings, or posted forms to attempt to provide it.
- Model validation uses optional attributes on the model type to ensure the model object conforms to certain data requirements.
Preventing Large Controllers
The mediator design pattern reduces coupling between classes while allowing communication between them. Use the MediatR Nuget package.