Question

我正在尝试为实体框架核心实现我的缓存变体。我所做的就是继承

公共类CustomQueryCompiler：QueryCompiler

然后我尝试将分布式缓存注入到CustomQueryCompiler的构造函数中，但无法解决它。得到此错误：

System.InvalidOperationException: Unable to resolve service for type 'Microsoft.Extensions.Caching.Distributed.IDistributedCache' while attempting to activate 'WebApplication6.CustomQueryCompiler'.
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateArgumentCallSites(Type serviceType, Type implementationType, CallSiteChain callSiteChain, ParameterInfo[] parameters, Boolean throwIfCallSiteNotFound)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateConstructorCallSite(Type serviceType, Type implementationType, CallSiteChain callSiteChain)

我不明白为什么以及如何解决它。

我的创业公司是这样的：


    public void ConfigureServices(IServiceCollection services)
        {    
            services.AddDistributedRedisCache(options =>
                options.Configuration = "127.0.0.1:6379,password=P@55w0rd,allowAdmin=true,ssl=False,abortConnect=false");

            services.AddDbContext<AppDbContext>(options =>
                {
                    options.UseSqlServer(Configuration.GetConnectionString("Default"));
                    options.ReplaceService<IQueryCompiler, CustomQueryCompiler>();
                }
            ); 
            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
        }

CustomQueryCompiler的构造函数

  public class CustomQueryCompiler : QueryCompiler
    {
        private readonly IQueryModelGenerator _queryModelGenerator;
        private readonly IDistributedCache _distributedCache;

        public CustomQueryCompiler(IQueryContextFactory queryContextFactory,
            ICompiledQueryCache compiledQueryCache,
            ICompiledQueryCacheKeyGenerator compiledQueryCacheKeyGenerator,
            IDatabase database,
            IDiagnosticsLogger<DbLoggerCategory.Query> logger,
            ICurrentDbContext currentContext,
            IQueryModelGenerator queryModelGenerator, IDistributedCache distributedCache) : 
            base(queryContextFactory, compiledQueryCache, compiledQueryCacheKeyGenerator, database, logger, currentContext, queryModelGenerator)
        {
            _queryModelGenerator = queryModelGenerator;
            _distributedCache = distributedCache;
        }

Answer 1

弄清楚。 EF Core维护自己的IoC容器。因此，您需要将现有服务传递到其容器中。

我不得不做下一件事。希望它可以帮助别人。

  services.AddEntityFrameworkSqlServer();
  services.Replace(new ServiceDescriptor(typeof(IQueryCompiler), typeof(CustomQueryCompiler), ServiceLifetime.Transient));

  services.AddDbContext < AppDbContext > (options => {
   options.UseSqlServer(Configuration.GetConnectionString("Default"));

   options.UseInternalServiceProvider(services.BuildServiceProvider());
  });

将我的依赖项注入CustomQueryCompiler

1 个答案: