Ef Core 2将值设置为运行时被忽略的属性 [英] Ef Core 2 set value to ignored property on runtime

问题描述

我有一个实体，其布尔属性名为 ReadOnly，该属性的值取决于使用该应用程序的用户。

I have an entity with boolean property named "ReadOnly", the value of this property depends on which user is using the application.

在DbContext中，我配置了

In the DbContext i configured the property to be ignored.

public class MyDbContext : DbContext
{
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Entity>().Ignore(e => e.ReadOnly);
    }
}

如何设置运行时计算出的正确值，因此

How can i set the correct value calculated on runtime so that i haven't to remind to calculate the property everytime?

编辑：我在想类似

int loggedUserId = HttpSession.UserId;
modelBuilder.Entity<Entity>().Property(e => e.ReadOnly).Value = loggedUserId > 5;

这样，根据用户登录到应用程序，我始终具有正确的值。

This way i have always the correct value based on User logged to the application.

推荐答案

我发现AutoMapper具有满足我需要的ProjectTo函数，ProjectTo会告诉AutoMapper的映射引擎向IQueryable发出select子句

I found out that AutoMapper has ProjectTo function that does what i need, ProjectTo will tell AutoMapper’s mapping engine to emit a select clause to the IQueryable

我的配置示例：

 configuration.CreateMap(typeof(Entity), typeof(Entity))
    .ForMember(nameof(Entity.IsReadOnly), opt.MapFrom(src => currentUserResolver.GetUserId() > 5));

用法：

myDbSet.AsQueryable().ProjectTo<TEntity>();

http://docs.automapper.org/en/stable/Queryable-Extensions.html

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