如何使用.NET Core中的默认依赖项注入从父级创建子级作用域? [英] How to create a child scope from the parent with default dependency injection in .NET Core?

问题描述

我正在构建一个控制台.NET Core应用程序.它定期运行可以完成某些工作的方法.如何使ServiceProvider的行为与在ASP.NET Core应用程序中的行为相同.我希望它在方法开始执行时解析作用域服务，并在方法结束时处置已解析的服务.

I am building a console .NET Core application. It periodically runs a method that does some work. How do I make ServiceProvider behave in the same way it behaves in ASP.NET Core apps. I want it to resolve scoped services when the method begins it's execution and dispose the resolved services at the end of the method.

// pseudocode

globalProvider.AddScoped<ExampleService>();

// ...

using (var scopedProvider = globalProvider.CreateChildScope())
{
    var exampleService = scopedProvider.Resolve<ExampleService>();
}

推荐答案

使用IServiceProvider.CreateScope()方法创建本地范围:

Use IServiceProvider.CreateScope() method to create a local scope:

var services = new ServiceCollection();
services.AddScoped<ExampleService>();
var globalProvider = services.BuildServiceProvider();

using (var scope = globalProvider.CreateScope())
{
    var localScoped = scope.ServiceProvider.GetService<ExampleService>();

    var globalScoped = globalProvider.GetService<ExampleService>();
}

可以很容易地对其进行测试:

It can be easily tested:

using (var scope = globalProvider.CreateScope())
{
    var localScopedV1 = scope.ServiceProvider.GetService<ExampleService>();
    var localScopedV2 = scope.ServiceProvider.GetService<ExampleService>();
    Assert.Equal(localScopedV1, localScopedV2);

    var globalScoped = globalProvider.GetService<ExampleService>();
    Assert.NotEqual(localScopedV1, globalScoped);
    Assert.NotEqual(localScopedV2, globalScoped);
}

文档:服务寿命和注册选项.

参考 Microsoft.Extensions.DependencyInjection 或只是 Microsoft.AspNetCore.All 包以使用上面的代码.

Reference Microsoft.Extensions.DependencyInjection or just Microsoft.AspNetCore.All package to use the code above.

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