从 dbContext 获取 IEnumerable<SelectListItem>

Question

我有以下数据库class

namespace Project.Web.Repository
{
    public class Database : DbContext
    {

        public Database(DbContextOptions<Database> options) : base(options)
        {
        }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
        }

        public virtual DbSet<SelectListItem> SelectListItem {get; set;}

        public IEnumerable<SelectListItem> Categories()
        {
            var query = "SELECT Id as [Value], Name as [Text] FROM enum.Category";
            IEnumerable<SelectListItem> items = SelectListItem.FromSql(query).ToList<SelectListItem>();
            return items;
        }

    }
}

但调用后

_database.BrandCategories();

我收到了

Exception has occurred: CLR/System.InvalidOperationException
An exception of type 'System.InvalidOperationException' occurred in Microsoft.EntityFrameworkCore.dll but was not handled in user code: 'The entity type 'SelectListGroup' requires a primary key to be defined.'

通过 EF Core 从数据库中获取 select 列表的首选方法是什么？我是否需要为每个 table 创建 POCO class 并在获取数据后将 POCO class 转换为 SelectListItem 集合？

Answer 1

您只能通过 FromSql 映射到实体类型，即属于您的上下文的类型。但是，一旦到达那里，您就可以使用 LINQ 的 Select 映射到类似 SelectListItem:

的内容

var items = categories.Select(x => new SelectListItem 
    { 
        Value = x.Id, 
        Title = x.Name 
    }
);

从 dbContext 获取 IEnumerable<SelectListItem>

Get IEnumerable<SelectListItem> from dbContext

dbcontext

entity-framework-core

asp.net-core