How deeply does .NET MAUI in Action cover transient lifetime?

Explains lifetime trade-offs, navigation expectations, state concerns, and the AddTransient registration step.

Transient lifetime

A transient scope is a dependency-injection lifetime in which a new service instance is created each time the service is requested.

A transient lifetime creates a new dependency-injection service instance each time it is requested. In a .NET MAUI UI app, this is useful when each page or view model should begin with clean state. section 8.2

Use transient registration when:

A page should be recreated for each request, avoiding stale values and preserving state elsewhere. section 8.2
A view model should provide a clean instance alongside a newly requested page. section 8.2
A navigation style expects fresh pages, unlike Shell navigation, which commonly keeps pages as singletons. section 8.2

Registering a transient page

Register a modal LoginPage manually in MauiProgram.cs with builder.Services.AddTransient<LoginPage>();. Resolve it through dependency injection when navigation needs a new page. section 8.2.1

Table 8.2 Scope lifetimes for different dependencies in a .NET MAUI app (view table figure)

Dependency type	Scope	Reasoning
Pages	Transient	We should expect a new instance of a page every time we request one. Persisting values across different instances of a page could cause problems, so we’re better off persisting state elsewhere and using transient instances of pages.
ViewModels	Transient	Just like pages, our ViewModels should be transient, so we know we’ve got a clean instance every time we get a new ViewModel.
Services	Singleton	We should only expect one instance of a service for the running lifetime of an app. Instantiating multiple copies of a database or a service responsible for communicating with an API is a waste of resources and can lead to data conflicts. Services should be singletons and can therefore be where we persist app-wide state. We can inject these singleton instances into ViewModels.

Compare recommended lifetimes for pages, view models, and services in a .NET MAUI app. section 8.2

How .NET MAUI in Action covers it

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Also explained in

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ASP.NET Core in Action, 3eA transient lifetime is a dependency-injection lifetime policy that creates a new service instance each time the service is requested.

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Related concepts

ASP.NET Coreused by · ASP.NET Core is Microsoft’s cross-platform, open-source framework for building web applications and services on the .NET platform.
servicekind of · A service is an application component that provides defined capabilities to other components through an interface.
service lifetimekind of · A service lifetime is a dependency-injection rule that determines when service instances are created, how long they are retained, and when they are disposed.
Invoke methodused by · Invoke is the conventional ASP.NET Core middleware method that processes an HTTP request and can receive dependencies through its parameters.
dependency graphproduces · A dependency graph is a graph whose nodes represent entities and whose edges represent dependency relationships among them.

This explainer was generated by Manning's knowledge graph from the text of .NET MAUI in Action. The section links point to the parts of the book it draws on.