如何查询实现接口的所有表

Question

我已经为我的一些实体类实现了一个接口:

public partial class Order : IReportable
{
   public string TableName { get { return "Order"; } }
}

public partial class Client: IReportable
{
 public string TableName { get { return "Client"; } }
}


public interface IReportable
{
    string TableName { get; }
}

然后我将其添加到DbContext:

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

当我尝试查询实现此接口的所有表时(如此处所示):

var result = from reportabletable in db.IReportable
             where reportabletable.TableName == table_name
            select reportabletable

我得到以下异常:

未映射"Report.DataAccess.IReportable"类型.使用Ignore方法或NotMappedAttribute数据批注检查未明确排除类型.验证类型是否已定义为类,不是原始类型还是通用类型,并且不从EntityObject继承.

Answer 1

我会选择这样的东西:

创建此扩展方法

public static class DbContextExtensions
{
    public static IEnumerable<T> SetOf<T>(this DbContext dbContext) where T : class
    {
        return dbContext.GetType().Assembly.GetTypes()
            .Where(type => typeof(T).IsAssignableFrom(type) && !type.IsInterface)
            .SelectMany(t => Enumerable.Cast<T>(dbContext.Set(t)));
    }
}

并像这样使用它:

using (var db = new dbEntities())
{
 var result = from reportabletable in db.SetOf<IReportable>()
         where reportabletable.TableName == table_name
        select reportabletable
}