我如何 UseMiddleware<Type>(...) 并传入选项？

Question

我试图了解 ASP.NET Core 管道的工作原理。我想使用StaticFileMiddleware并传入一些选项。

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    var staticFileOptions = new StaticFileOptions();
    app.UseMiddleware<Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware>(staticFileOptions);
}

当我运行我的应用程序时，出现以下错误

System.InvalidOperationException: A suitable constructor for type 'Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware' could not be located. Ensure the type is concrete and services are registered for all parameters of a public constructor.
    at Microsoft.Extensions.Internal.ActivatorUtilities.CreateInstance(IServiceProvider provider, Type instanceType, Object[] parameters)
    at Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.<>c__DisplayClass3_0.<UseMiddleware>b__0(RequestDelegate next)
    at Microsoft.AspNetCore.Builder.Internal.ApplicationBuilder.Build()
    at Microsoft.AspNetCore.Hosting.Internal.WebHost.BuildApplication()

我知道我可以使用

app.UseStaticFiles(staticFileOptions);

但是，由于这是一个学习练习，我想换个说法。

Answer 1

这是我对同一问题的处理方法。

只需使用您想要传递的属性创建新类：

public class LoggingOption
{
    public bool ToLog { get; set; }
}

这是如何初始化

app.UseMiddleware<LoggingMiddleware>(Options.Create(new LoggingOption{ ToLog = true }));

这是构造函数

 public LoggingMiddleware(RequestDelegate next, ILoggerFactory loggerFactory, IOptions<LoggingOption> options)
        {
            _next = next;
            _logger = loggerFactory.CreateLogger<LoggingMiddleware>();
            _toLog = options.Value.ToLog;
        }

Answer 2

代替

app.UseMiddleware<Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware>(staticFileOptions);

使用

app.UseMiddleware<Microsoft.AspNetCore.StaticFiles.StaticFileMiddleware>(Microsoft.Extensions.Options.Options.Create(staticFileOptions));

（或将 粘贴Microsoft.Extensions.Options为 using 和 call Options.Create）

实际代码中UseStaticFiles是这样实现的