需要帮助尝试在 EntityFramework 中 EagerLoad 一些数据

发布于 2024-09-19 07:14:46 字数 456 浏览 6 评论 0原文

我正在尝试对 EF 实体进行一些预先加载。

所以，如果实体名为 Orders .. 那么我想我会执行以下操作...

_someContext.Orders.Include("Whatever") ....

但是问题是，我有一个像下面这样的方法...

public IQueryable<Order> Find(Expression<Func<Order, bool>> predicate)
{
    return CurrentContext.Orders.Where(predicate);
}

效果很好..但是我可以利用 Expression 谓词将 Include("whatever") 包含在那里，而不必添加另一个方法参数？

原文

I'm trying to do some eager loading on an EF Entity.

so, if the entity is called Orders .. then I guess i would do the following...

_someContext.Orders.Include("Whatever") ....

But the problem is, I have a method like the following ...

public IQueryable<Order> Find(Expression<Func<Order, bool>> predicate)
{
    return CurrentContext.Orders.Where(predicate);
}

which works great .. but can i leverage the Expression predicate to include the Include("whatever") in there, instead of having to add another method parameter?

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小忆控 2024-09-26 07:14:47

我不这么认为。由于谓词和 ObjectQuery.Where 方法 一般来说，与 Include 的急切加载无关。虽然您可以创建一个扩展方法，但这并不能避免您使用另一个参数来指定包含：

public IQueryable<Order> Find(Expression<Func> predicate, string include) {
    return CurrentContext.Orders.Where(predicate, include);
}

public static ObjectQuery<T> Where<T>(this ObjectQuery<T> entity, Expression<Func<T, bool>> predicate, string include) {
    return (ObjectQuery<T>)entity.Include(include).Where<T>(predicate);
}

I don't think so. Since the predicate and ObjectQuery.Where Method in genral has nothing to do with eager loading by Include. You can create a extension method though, but that does not save you from having yet another parameter for specifying the include:

public IQueryable<Order> Find(Expression<Func> predicate, string include) {
    return CurrentContext.Orders.Where(predicate, include);
}

public static ObjectQuery<T> Where<T>(this ObjectQuery<T> entity, Expression<Func<T, bool>> predicate, string include) {
    return (ObjectQuery<T>)entity.Include(include).Where<T>(predicate);
}

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