View component
A view component is a reusable presentation component that encapsulates application logic and renders a portion of a user interface or response.
Pro ASP.NET Core 7, Tenth Edition
The ViewComponent base class is the ASP.NET Core MVC base class that supplies view-component behavior and access to request context.
- How it is used
- Supplies reusable navigation and cart-summary content inside layouts without making it part of each action’s view model.
- How deep it goes
- Works through class discovery, injected data, Razor rendering, parent arguments, and request context rather than framework internals.
- Examples
- Builds category navigation and a shopping-cart summary, then demonstrates an asynchronous page-size display.
- What you can do after
- Build it from scratch: inject a service, implement Invoke, render a Razor view, and embed the result in a layout.
Read how Pro ASP.NET Core 7, Tenth Edition explains view component →
ASP.NET Core in Action, 3e
ViewComponent is the ASP.NET Core base class from which custom view component classes can derive.
- How it is used
- Renders independent page sections that need both business logic and HTML without adding those responsibilities to the main Razor page.
- How deep it goes
- Shows inheritance, InvokeAsync, dependency injection, parameter passing, and view-location conventions through a custom component.
- Examples
- Uses a current-user recipe component, plus shopping carts and dynamic menus as other independent page sections.
- What you can do after
- Build it from scratch by deriving from ViewComponent, implementing InvokeAsync(), supplying a component view, and invoking it from Razor.
Read how ASP.NET Core in Action, 3e explains view component →
Related concepts
- dependency injectionuses · Dependency injection is a software design technique in which a component receives its dependencies from outside rather than creating or locating them internally.
- subtemplatecontrasts with · A subtemplate is a reusable template fragment that can be rendered independently or included within another template to produce part of an output.
- InvokeAsyncused by · InvokeAsync is an API method for invoking an operation asynchronously and obtaining or scheduling its result.
- contextuses · Context is the surrounding information, state, or circumstances that condition how an entity, event, or task is interpreted or how a system behaves.
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