.NET 5 IOptionsSnapshot：无法解析作用域服务

Question

当我尝试解析 IOptionsSnapshot 服务时出现以下异常：

'Cannot resolve scoped service 'Microsoft.Extensions.Options.IOptionsSnapshot`1[Test.MyOptions]' from root provider.'

我把测试代码留在下面，如果有人能告诉我问题。

主要

using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using System.IO;

class Program
{
    static void Main(string[] args)
    {
        var configuration = new ConfigurationBuilder()
            .SetBasePath(Directory.GetCurrentDirectory())
            .AddJsonFile("AppSettings.json", optional: false, reloadOnChange: true)
            .AddJsonFile("MyOptions.json", optional: false, reloadOnChange: true)
            .AddEnvironmentVariables()
            .Build();

        var services = new ServiceCollection();
        var provider = services.Configure<MyOptions>(configuration.GetSection(nameof(MyOptions))).BuildServiceProvider(true);

        var test = provider.GetRequiredService<IOptionsSnapshot<MyOptions>>();
    }
}

我的选项class

public class MyOptions
{
    public int Value { get; set; }
}

MyOptions.json

{
  "MyOptions": {
    "Value": 10
  }
}

Answer 1

IOptionsSnapshot<T> 注册为 scoped 服务，这意味着您需要创建一个服务范围，然后使用该范围进行解析：

using (var scope = provider.CreateScope())
{
    var scopedProvider = scope.ServiceProvider;
    var test = scopedProvider.GetRequiredService<IOptionsSnapshot<MyOptions>>();

   //...
}

.NET 5 IOptionsSnapshot：无法解析作用域服务

.NET 5 IOptionsSnapshot: Cannot resolve scoped service

c#

dependency-injection

.net-5