包括过滤器子集合 [英] Include filter child collection

问题描述

我很难为LINQ查询中的包含项添加一些过滤条件.我的查询就像

I have some difficulty to add some filter condition for included items in my LINQ query. My query is like

var item = _Context.Order.Include("Inner")
           .Include("Inner.first")
           .Include("Inner.second")
           .Where(x => ( !(x.IsDeleted) && (x.IsActive) && 
                 (x.itemid == id))).FirstOrDefault();

            

在上面的代码内部"中，是另一个项目列表.现在我需要过滤内部项目.我只需要过滤条件为inner.isDeleted = true的内部项目.

In the above code "Inner" is another list of item. Now i need to filter inner items. I only need inner item with filter condition inner.isDeleted = true.

查询应返回类似的类，

public class Order
{
    public string Name { get; set; }
    public List<InnerDetails> Inner{ get; set; }
    public bool IsDeleted { get; set; }
}

和类似InnerDetails的类

and InnerDetails class like

public class InnerDetails 
{
    public string Sample { get; set; }
    public bool IsDeleted { get; set; }
    public int firstId { get; set; }
    public int secondID { get; set; }
    public First first{ get; set; }
    public Second second{ get; set; }
}

有人可以建议我做一个更好的方法，因为我是LINQ和EF的新手吗?

Can anyone suggest me a better approach to do this because i am new in LINQ and EF?

推荐答案

免责声明:我是该项目的所有者实体框架增强版

Disclaimer: I'm the owner of the project Entity Framework Plus

EF +查询IncludeFilter功能允许过滤相关实体.

EF+ Query IncludeFilter feature allows filtering related entities.

var item = _Context.Order
           .IncludeFilter(x => x.Inner.Where(y => y.IsDeleted))
           .IncludeFilter(x => x.Inner.Where(y => y.IsDeleted).Select(y => y.first))
           .IncludeFilter(x => x.Inner.Where(y => y.IsDeleted).Select(y => y.second))
           .Where(x => ( !(x.IsDeleted) && (x.IsActive) && 
                 (x.itemid == id))).FirstOrDefault();

注意:您不能混合使用Include&IncludeFilter.

Note: You cannot mix Include & IncludeFilter.

Wiki: EF +查询IncludeFilter

回答子问题

但是我们只能使用EF来实现

But we can achieve this using EF only

是的，我的图书馆在幕后使用了与投影相似的解决方案

Yes, under the hood, my library uses a similar solution as projection

var item = _Context.Order.Select(x => new {
                Order = x,
                Inner = x.Inner.Where(y => y.IsDeleted),
                first = x.Inner.Where(y => y.IsDeleted).Select(y => y.first)
                second = x.Inner.Where(y => y.IsDeleted).Select(y => y.second)
            })
            .Where(x => ( !(x.IsDeleted) && (x.IsActive) && (x.itemid == id)))
            .FirstOrDefault()
            .Select(x => x.Order)
            .FirstOrDefault();

注意:代码尚未经过测试

回答评论

我在EF Core中遇到了这个问题.您是否还将在EF + Core版本中实现IncludeFilter

I came across this issue in EF Core. Are you going to implement IncludeFilter also in the EF+Core version

从v1.10.0开始，EF Core 2.x现在支持 IncludeFilter

Starting from the v1.10.0, the IncludeFilter is now supported in EF Core 2.x

请参阅:发行说明

回答子问题

过滤后如何包含

我们还没有 ThenInclude .

因此，您需要再次将 IncludeFilter 与所有过滤器一起使用，并浏览要包含的列表或实体.

So you need to use IncludeFilter again with all filter and navigate through the list or entity you want to include.

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