ASP.NET Core (twenty-five) dependencies inject Lazy lazy lazy initialization

Little scum · Posted on 10/10/2023 9:14:31 PM

Requirements: Add services ASP.NET Core, inject services through constructors, and want to delay initialize the implementation class (different logical processing according to the HTTP context request information), and think of using Lazy<T> for lazy for lazy initialization.

Review:

How Lazy in C# keeps threads safe
https://www.itsvse.com/thread-10621-1-1.html

C# performance optimization: Lazy initializes lazy with <T>a delay
https://www.itsvse.com/thread-7700-1-1.html

Inject directly into the interface

The constructor is injected directly into the interface service, and the code is as follows:

Login is visible.

The execution order is as follows:

You can see the following execution order: IA implementation class -> HomeController console -> index method

Initialize with Lazy delay

If the controller constructor changes IA to Lazy<IA>, the error will look like this:

InvalidOperationException: Unable to resolve service for type 'System.Lazy`1[WebApplication6.IA]' while attempting to activate 'WebApplication6.Controllers.HomeController'.

The error is due to the fact that we have not registered for Lazy-related services, we need to register a Lazy<> generic service, the code is as follows:

Login is visible.

Add to Service:

Login is visible.

The execution order is as follows:

You can see the execution order: HomeController console -> Index method -> IA implementation class, you can see itIA interface delay initializationwill instantiate the IA implementation object when called.

(End)

[Source] ASP.NET Core (twenty-five) dependencies inject Lazy lazy lazy initialization

Related Posts

Sections viewed