c# - 在 ConfigureServices 中注入(inject)依赖

Question

在我的 ASP.Net Core 应用程序中，我需要在 ConfigureServices 方法中注入(inject)一些依赖项(在我的例子中是一个存储库)。

问题是该方法不允许使用多个参数来注入(inject)依赖项。该怎么做？

这是我的代码

public void ConfigureServices(IServiceCollection services)
{
    services.AddOptions();

    // ... 
    services.AddSingleton<ITableRepositories, TableClientOperationsService>();

    // Add framework services.
    services.AddOpenIdConnect(options =>
    {
        // options.ClientId = ...
        options.Events = new OpenIdConnectEvents
        {
            OnTicketReceived = async context =>
            {
                var user = (ClaimsIdentity)context.Principal.Identity;
                if (user.IsAuthenticated)
                {
                    // ... 
                    // vvv 
                    // HERE, I need the ITableRepositories repository; 
                    // vvv
                    var myUser = await repository.GetAsync<Connection>(userId);
                    // ... 
                }
                return;
            }
        };
    });
}

如何在此处注入(inject)依赖项？

编辑:

按照 Chris 的想法(如下)，这似乎可行:

public class Startup
{
    // private repository, used in ConfigureServices, initialized in Startup
    ITableRepositories repository;

    public Startup(IHostingEnvironment env)
    {
        var builder = new ConfigurationBuilder()
        // ... etc etc
        Configuration = builder.Build();

        // init repository here
        this.repository = new TableClientOperationsService();
    }

Answer 1

您可以通过当前上下文的HttpContext.RequestServices访问服务容器。

public void ConfigureServices(IServiceCollection services) {
    services.AddOptions();

    // ... 
    services.AddSingleton<ITableRepositories, TableClientOperationsService>();

    // Add framework services.
    services.AddOpenIdConnect(options => {
        // options.ClientId = ...
        options.Events = new OpenIdConnectEvents {
            OnTicketReceived = async context => {
                var user = (ClaimsIdentity)context.Principal.Identity;
                if (user.IsAuthenticated) {
                    // ... 

                    // get the ITableRepositories repository
                    var repository = context.HttpContext.RequestServices.GetService<ITableRepositories>();
                    var myUser = await repository.GetAsync<Connection>(userId);

                    // ... 
                }
                return;
            }
        };
    });
}

因此从技术上讲，您不需要访问 ConfigureServices 中的依赖项，因为内联表达式可以提取到它自己的函数中。

public void ConfigureServices(IServiceCollection services) {
    services.AddOptions();

    // ... 
    services.AddSingleton<ITableRepositories, TableClientOperationsService>();

    // Add framework services.
    services.AddOpenIdConnect(options => {
        // options.ClientId = ...
        options.Events = new OpenIdConnectEvents {
            OnTicketReceived = TicketReceived
        };
    });
}

private async Task TicketReceived(TicketReceivedContext context) {
    var user = (ClaimsIdentity)context.Principal.Identity;
    if (user.IsAuthenticated) {
        // ... 

        // get the ITableRepositories repository
        var repository = context.HttpContext.RequestServices.GetService<ITableRepositories>();
        var myUser = await repository.GetAsync<Connection>(userId);

        // ... 
    }
    return;
}