Entity Framework 6.0 对枚举的支持/实体添加后会有主键反回_.NET_编程开发_程序员俱乐部

实验

直接上代码,看结果

实体类

[Flags]
    public enum FlagsEnum
    {
        Day = 1,
        Night = 2
    }
    public class EntityWithEnum
    {
        public int ID { get; set; }

        public FlagsEnum ValidTime { get; set; }

    }

数据库上下文

public partial class CodeFirstModel : DbContext
   {
        public CodeFirstModel()
            : base("name=CodeFirstModel")
        {
        }

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

Sql server LocalDb的连接字符串

<connectionStrings>
    <add name="CodeFirstModel" connectionString="data source=(LocalDb)\MSSQLLocalDb;initial catalog=TestDb;integrated security=True;multipleactiveresultsets=True;application name=EntityFramework" providerName="System.Data.SqlClient" />
  </connectionStrings>

主函数

static void Main(string[] args)
        {
            //CreateDatabaseIfNotExists
            //DropCreateDatabaseIfModelChanges
            //DropCreateDatabaseAlways
            Database.SetInitializer(new DropCreateDatabaseIfModelChanges<CodeFirstModel>());
            using (var context = new CodeFirstModel())
            {
                context.Database.Initialize(true);
            }


            using(CodeFirstModel db = new CodeFirstModel())
            {
        EntityWithEnum entity = new EntityWithEnum() { ValidTime = FlagsEnum.Day };
                db.EntityWithEnum.Add(entity);

                entity = new EntityWithEnum() { ValidTime = FlagsEnum.Night };
                db.EntityWithEnum.Add(entity);


                entity = new EntityWithEnum() { ValidTime = FlagsEnum.Night| FlagsEnum.Day };
                db.EntityWithEnum.Add(entity);

                db.SaveChanges();
                Console.WriteLine("{0}:\t{1}", entity.ID, entity.ValidTime);
                Console.WriteLine("-------------------");

                var entitys = from e in db.EntityWithEnum
                              where e.ValidTime.HasFlag(FlagsEnum.Day)
                              select e;

                foreach (var item in entitys)
                {
                    Console.WriteLine("{0}:\t{1}", item.ID, item.ValidTime);
                }
                

            }
            Console.ReadKey(true);
}

运行结果

结论

Entity Framework 6.0 的 LINQ 是可以直接写 枚举的 HasFlags 方法的.

Add 的实体在 数据库保存后,会将数据库生成好的主键读出来.不用再写LINQ 再查一遍了.