如何将实体框架包含扩展方法引入通用IQueryable< TSource>。 [英] How to brings the Entity Framework Include extention method to a Generic IQueryable<TSource>

问题描述

这是东西。

我有一个接口，我想使用 Include 扩展方法，谁属于 EntityFramework 库，属于我的 IRepository 层，而无需了解 EntityFramework 。

I have an interface, and I would to put the Include extension method, who belongs to EntityFramework library, to my IRepository layer wich dont needs to knows about EntityFramework.

public interface IRepository<TEntity>
{
    IQueryable<TEntity> Entities { get; }

    TEntity GetById(long id);
    TEntity Insert(TEntity entity);
    void Update(TEntity entity);
    void Delete(TEntity entity);
    void Delete(long id);
}

所以我有扩展方法：

public static class IncludeExtension 
{
    static IQueryable<TEntity> Include<TEntity>(this IQueryable<TEntity> query, 
        string path)
    {
        throw new NotImplementedException();
    }
}

但是我不知道如何实现此层，然后将其发送到我的EntityFramework（或将实现IRepository的任何人）进行处理。

But I don't know how to implement it in this layer, and I would to send it to my EntityFramework (or whatever who will implement the IRepository) to deal with.

我需要使用扩展方法对接口进行相同处理。

I need same to a Interface with a extension method.

有光吗？

推荐答案

这个问题有点老了，但是，如果您或其他任何人仍在寻找，则有两种独立于EF的解决方案：

This question is a bit old, but here are two EF-independent solutions if you or anyone else is still looking:

1。基于反射的解决方案

如果 IQueryable ，则.NET Framework只能使用此解决方案不会转换为 DbQuery 或 ObjectQuery 。跳过这些强制转换（及其提供的效率），即可将解决方案与Entity Framework分离。

This solution is what the .NET Framework falls back to if the IQueryable does not cast to a DbQuery or ObjectQuery. Skip these casts (and the efficiency it provides) and you've decoupled the solution from Entity Framework.

public static class IncludeExtension  
{ 
    private static T QueryInclude<T>(T query, string path) 
    { 
        MethodInfo includeMethod = query.GetType().GetMethod("Include", new Type[] { typeof(string) });

        if ((includeMethod != null) && typeof(T).IsAssignableFrom(includeMethod.ReturnType))
        {
           return (T)includeMethod.Invoke(query, new object[] { path });
        }

        return query;
    }

    public static IQueryable<T> Include<T>(this IQueryable<T> query, string path) where T : class
    {
        return QueryInclude(query, path);
    }

    // Add other Include overloads.
} 

2。基于Dyanmics的解决方案

此处， QueryInclude< T> 方法使用动态类型以避免反射。

Here the QueryInclude<T> method uses the dynamic type to avoid reflection.

public static class IncludeExtension  
{ 
    private static T QueryInclude<T>(T query, string path) 
    { 
        dynamic querytWithIncludeMethod = query as dynamic;

        try
        {
            return (T)querytWithIncludeMethod.Include(path);
        }
        catch (RuntimeBinderException)
        {
            return query;
        }
    }

    public static IQueryable<T> Include<T>(this IQueryable<T> query, string path) where T : class
    {
        return QueryInclude(query, path);
    }

    // Add other Include overloads.
} 

这篇关于如何将实体框架包含扩展方法引入通用IQueryable< TSource>。的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！