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c# - 具有阴影属性的种子对象

问题描述

我正在尝试使用 Entity Framework core 3.1 为使用阴影属性的对象播种，但是当我尝试创建迁移时，我得到：

The seed entity for entity type 'MyObject' cannot be added because there was no value provided for the required property 'Created'.

属性“Created”是在 OnModelCreating 中添加的影子属性，因此我无法在模型配置中访问它。Microsoft 文章Data Seeding说：“如果实体类型有任何处于影子状态的属性，则可以使用匿名类来提供值……”我也尝试过，但遇到了同样的错误。

这是我的配置：

protected override void OnModelCreating( ModelBuilder modelBuilder )
{
    // Tried this before and after the shadow properties, same error
    modelBuilder.ApplyConfiguration( new MyObjectConfiguration() );

    // Tried to seed here too instead of in the MyObjectConfiguration
    //modelBuilder.Entity<Brokerage>().HasData( new
                            //{
                                //Id = 1,
                                //Name = "A Really Cool Object",
                                //PhoneNumber = "1234567891"
                            //} );

    // Create shadow properties
    foreach ( var entityType in modelBuilder.Model.GetEntityTypes()
          .Where( e => typeof( IAuditable ).IsAssignableFrom( e.ClrType ) ) )
    {
        modelBuilder.Entity( entityType.ClrType )
            .Property<DateTime>( "Created" );

        modelBuilder.Entity( entityType.ClrType )
            .Property<DateTime>( "Modified" );

        modelBuilder.Entity( entityType.ClrType )
            .Property<string>( "CreatedBy" );

        modelBuilder.Entity( entityType.ClrType )
            .Property<string>( "ModifiedBy" );
    }

    base.OnModelCreating( modelBuilder );
}


public class BrokerageConfiguration : IEntityTypeConfiguration<MyObject>
{
    public void Configure( EntityTypeBuilder<MyObject> builder )
    {
        ...

        //builder.Entity<MyObject>()
        //    .HasData( new { Id = 1, Name = "A Really Cool Object", PhoneNumber = "1234567891" } );

        builder.HasData
        (
            new MyObject
            {
                Id = 1,
                Name = "A Really Cool Object",
                PhoneNumber = "1234567891"
            }
        );
    }
}

如何播种使用阴影属性的数据？

标签： c#entity-framework-coreseed

解决方案

为了完整起见（因为我自己正在寻找解决方案），使用匿名类将是上面评论的解决方案：

modelBuilder.Entity<Brokerage>().HasData(new
{
    Id = 1,
    Name = "A Really Cool Object",
    PhoneNumber = "1234567891",
    CreatedBy = "sysdba",
    Created = DateTime.Now,
    ModifiedBy = "sysdba",
    Modified = DateTime.Now
});

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