缺少RelationalTypeMapping实体框架核心

Question

我已经使用流利的模型构建器手动设置了Entity Framework映射，并且在查询时一切正常，但是在尝试创建实体时，这是我得到的：

  

值不能为null。参数名称：relationalTypeMapping

这是堆栈跟踪：

  

在Microsoft.EntityFrameworkCore.Utilities.Check.NotNull [T]（T值，字符串parameterName）
  在Microsoft.EntityFrameworkCore.Storage.Internal.TypeMappedRelationalParameter..ctor（字符串invariantName，字符串名称，RelationalTypeMapping，relationalTypeMapping，Nullable 1 nullable)
at Microsoft.EntityFrameworkCore.Storage.Internal.RelationalParameterBuilder.AddParameter(String invariantName, String name, IProperty property)
at Microsoft.EntityFrameworkCore.Storage.RelationalCommandBuilderExtensions.AddParameter(IRelationalCommandBuilder commandBuilder, String invariantName, String name, IProperty property) at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.CreateStoreCommand() at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.ExecuteAsync(IRelationalConnection connection, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.Update.Internal.BatchExecutor.ExecuteAsync(DbContext _, ValueTuple 2个参数，CancellationToken cancelToken）中          在Microsoft.EntityFrameworkCore.SqlServer.Storage.Internal.SqlServerExecutionStrategy.ExecuteAsync [TState，TResult]（TState状态，Func 4 operation, Func 4验证成功，CancellationToken cancelToken）处          在Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync（IReadOnlyList 1 entriesToSave, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.ChangeTracking.Internal.StateManager.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) at Microsoft.EntityFrameworkCore.DbContext.SaveChangesAsync(Boolean acceptAllChangesOnSuccess, CancellationToken cancellationToken) at FastTrack.EntityFramework.Services.EntityFrameworkService 3.CreateAsync（TDto dto）

这是我的映射代码：

   builder.Entity(typeof(Page), b =>
            {
                b.HasOne(typeof(Site))
                    .WithMany()
                    .HasForeignKey("SiteId")
                    .IsRequired();
            });

            builder.Entity<Site>()
                .HasMany(x => x.Pages)
                .WithOne(x => x.Site)
                .HasForeignKey("SiteId")
                .IsRequired();

以下是实体：

  public class Site
    {
        public int Id {get; set;}
        public string Name {get; set;}
        public IList<Page> Pages { get; set; }
        public string Domain { get; set; }
    }


   public class Page
    {
        public int Id {get; set;}
        public string Name {get; set;}
        public IList<PageSelector> PageSelectors { get; set; }
        public string Path { get; set; }
        public Site Site { get; set; }
        [ForeignKey("Site")]
        public int SiteId { get; set; }
    }

什么可能导致这种情况发生？映射似乎已正确设置，并且一切正常，直到我要向数据库中插入内容为止。