EF Core Fluent API 语句作为数据注释

问题描述

我可以在 EF Core 中用数据注释来写这个吗？

modelBuilder.Entity<DiagramComponent>()
                .HasOne(c => c.Compressor)
                .WithMany(c => c.Components);

解决方法

您将不得不再创建一个类：

public class DiagramComponentComponent
    {
        public int DiagramComponentId { get; set; }
        public int ComponentId { get; set; }

        [ForeignKey(nameof(DiagramComponentId))]
        public virtual DiagramComponent DiagramComponent { get; set; }

        [ForeignKey(nameof(ComponentId))]
        public virtual Component Component { get; set; }
    }

并向现有类添加属性：

public class DiagramComponent
    {
        public int CompressorId { get; set; }

        [ForeignKey(nameof(CompressorId))]
        [InverseProperty("DiagramComponents")]
        public virtual Compressor Compressor { get; set; }

[InverseProperty(nameof(DiagramComponentComponent.DiagramComponent))]
public virtual ICollection<DiagramComponentComponent> DiagramComponentComponents { get; set; }
    }
    public class Compressor
    {
        [InverseProperty(nameof(DiagramComponent.Compressor))]
        public virtual ICollection<DiagramComponent> DiagramComponents { get; set; }

    }
    public class Component
    {
[InverseProperty(nameof(DiagramComponentComponent.Component))]
public virtual ICollection<DiagramComponentComponent> DiagramComponentComponents { get; set; }

    }

并添加到 dbcontext:

modelBuilder.Entity<DiagramComponentComponent>(entity =>
            {
                entity.HasOne(d => d.DiagramComponent )
                    .WithMany()
                    .HasForeignKey(d => d.DiagramComponentId )
                    .OnDelete(DeleteBehavior.ClientSetNull)
          .HasConstraintName("FK_DiagramComponentComponent_Component_Diagram");

                entity.HasOne(d => d.Component)
                    .WithMany()
                    .HasForeignKey(d => d.ComponentId )
                    .OnDelete(DeleteBehavior.ClientSetNull)
                    .HasConstraintName("FK_DiagramComponentComponent_Component");
            });