NET 6 Minimal API - '找不到请求的公共静态 bool Request.TryParse(string, out Request) 方法

Question

使用 .NET 6 我在 Program.cs 中有以下最小 API：

WebApplicationBuilder builder = WebApplication.CreateBuilder();

builder.Services.AddMvcCore();
builder.Services.AddRouting();

await using WebApplication application = builder.Build();

application.UseRouting();

application.MapGet("/weatherforecast", () => { });

application.MapGet("countries", async ([FromQuery]Request request, IMediator mediator) => {
  Payload<List<Response>> payload = await mediator.Send(request);
  return Results.Ok(payload);
});

await application.RunAsync();

哪里Request：

public class Request { 
  public List<Int32> Ids { get; set; } = new List<Int32>();
} 

当我运行应用程序时，我在“国家/地区”端点上收到错误：

Exception thrown: 'System.InvalidOperationException' in Microsoft.AspNetCore.Http.Extensions.dll: 'No public static bool Request.TryParse(string, out Request) method found for request.'
   at Microsoft.AspNetCore.Http.RequestDelegateFactory.BindParameterFromValue(ParameterInfo parameter, Expression valueExpression, FactoryContext factoryContext, String source)
   at Microsoft.AspNetCore.Http.RequestDelegateFactory.CreateArgument(ParameterInfo parameter, FactoryContext factoryContext)
   at Microsoft.AspNetCore.Http.RequestDelegateFactory.CreateArguments(ParameterInfo[] parameters, FactoryContext factoryContext)
   at Microsoft.AspNetCore.Http.RequestDelegateFactory.CreateTargetableRequestDelegate(MethodInfo methodInfo, Expression targetExpression, FactoryContext factoryContext)
   at Microsoft.AspNetCore.Http.RequestDelegateFactory.Create(Delegate handler, RequestDelegateFactoryOptions options)
   at Microsoft.AspNetCore.Builder.EndpointRouteBuilderExtensions.Map(IEndpointRouteBuilder endpoints, RoutePattern pattern, Delegate handler, Boolean disableInferBodyFromParameters)
   at Microsoft.AspNetCore.Builder.EndpointRouteBuilderExtensions.MapMethods(IEndpointRouteBuilder endpoints, String pattern, IEnumerable`1 httpMethods, Delegate handler)
   at Microsoft.AspNetCore.Builder.EndpointRouteBuilderExtensions.MapGet(IEndpointRouteBuilder endpoints, String pattern, Delegate handler)

我缺少什么？

Answer 1

该错误基本上意味着 ASP.NET Core 不知道如何将您的查询字符串绑定到Request您定义的。

是Request自定义类型吗？如果是这样，您需要添加一个静态TryParse方法，该方法接受一个字符串（查询字符串）和Request您需要通过解析查询字符串来初始化的对象的输出参数。

您可以在官方文档中阅读更多相关内容