c# - .NET Core - FluentValidation 注入(inject)

Question

我正在创建 ASP.NET CORE (2.1) 项目并尝试使用 FluentValidation 库 ( https://fluentvalidation.net/ )。不幸的是，当我向我的 ApiController 发送请求时出现错误。

处理请求时发生未处理的异常。

InvalidOperationException: Unable to resolve service for type 'Core.Entities.Estimate' while attempting to activate 'Spinner.Features.Estimates.OnPost+CommandValidator'. Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateArgumentCallSites(Type serviceType, Type implementationType, CallSiteChain callSiteChain, ParameterInfo[] parameters, bool throwIfCallSiteNotFound)

这是我要验证模型和验证器的类:

public class Command : IRequest<AcceptCostEstimateResponse>
{
    public EstimateDTO Estimate { get; set; }

    public ClientHeaderDTO ClientHeader { get; set; }
}

public class CommandValidator : AbstractValidator<Command>
{
    public CommandValidator(Estimate configuration)
    {
        RuleFor(x => x.Estimate).NotNull();

        RuleFor(x => x.Estimate.Name).NotEmpty();

        RuleFor(x => x.Estimate.Variant).NotEmpty();

        RuleFor(x => x.ClientHeader.ClientName).NotEmpty();

        RuleFor(x => x.ClientHeader.RequestId).NotEmpty();
    }
}

这是我的 Startup.cs - 我存在依赖注入(inject)配置的地方:

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc()
        .SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
        .AddFluentValidation(fv => fv.RegisterValidatorsFromAssemblyContaining<Startup>());

    services.AddAutoMapper();

    services.AddMediatR();

    services.AddDbContextPool<SpinnerContext>(options => options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

    ConfigureCore(services);

    ConfigureRepositories(services);
}

我也尝试过以不同的方式配置 CommandValidator，就像这样，但这仍然没有帮助:

services.AddMvc()
        .SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
        .AddFluentValidation();

services.AddTransient<IValidator<Command>, CommandValidator>();

Answer 1

I removed Estimate configuration parameter inside CommandValidator constructor and now getting different error. An unhandled exception occurred while processing the request. NullReferenceException: Object reference not set to an instance of an object.

对于这个错误，是当Estimate 或ClientHeader 没有值时导致的，它们将为null，FluentValidation 将尝试访问他们的属性。

尝试以下选项:

• 更改 Command 以设置子属性。

  public class Command : IRequest<AcceptCostEstimateResponse>
  {
      public Command()
     {
         Estimate = new EstimateDTO();
         ClientHeader = new ClientHeaderDTO();
      }
      public EstimateDTO Estimate { get; set; }
      public ClientHeaderDTO ClientHeader { get; set; }
  }
  

• 更改 CommandValidator 以仅在其不为空时验证子属性。

      public CommandValidator()
  {
      //RuleFor(x => x.Estimate).NotNull();
  
      //RuleFor(x => x.Estimate.Name).NotEmpty();
  
      //RuleFor(x => x.Estimate.Variant).NotEmpty();
  
      //RuleFor(x => x.ClientHeader.ClientName).NotEmpty();
  
      //RuleFor(x => x.ClientHeader.RequestId).NotEmpty();
      RuleFor(x => x).NotNull();
  
      When(x => x != null, () =>
      {
          RuleFor(x => x.Estimate).NotNull();
  
          When(x => x.Estimate != null, () =>
          {
              RuleFor(x => x.Estimate.Name).NotEmpty();
  
              RuleFor(x => x.Estimate.Variant).NotEmpty();
          });
  
          RuleFor(x => x.ClientHeader).NotNull();
  
          When(x => x.ClientHeader != null, () =>
          {
              RuleFor(x => x.ClientHeader.ClientName).NotEmpty();
  
              RuleFor(x => x.ClientHeader.RequestId).NotEmpty();
          });
  
      });
  
  
  }