使用EF Core的“包含子项"中的OrderBy [英] OrderBy in Include child using EF Core

问题描述

在我的.NET Core/EF Core应用程序中，我有一个带有嵌套子对象列表的模型.检索实例时，我需要按孩子的属性之一对嵌套列表进行排序.通过查看类似问题并在EF Core上报告问题，我了解到我无法在检索实例时对嵌套列表进行排序.因此，现在尝试将其加载到内存后对其进行排序.但是在这里我也不成功.

In my .NET Core / EF Core application I have a model with a nested list of child objects. When I retrieve an instance, I need the nested list to be ordered by one of the child's properties. I understand from reviewing similar questions and reported issues on EF Core that I can't order the nested list on retrieving the instance. So now I am trying to sort it once loaded in memory. but here I am also not successful.

我正在使用存储库模式来访问DbContext.

I am using a Repository Pattern to access DbContext.

对列表进行排序的正确方法是什么，以便它始终返回从我的存储库中正确排序的列表?

What is the correct way to sort this list so that it always returns sorted correctly from my repository?

我最近尝试过:

    public async Task<Parent> GetParent(int id)
    {
        var loadedInMemory = context.Parents
            .Include(p => p.Children)
            .SingleOrDefaultAsync(p => p.Id == id);

        var result = loadedInMemory.Result.Children.OrderBy(c => c.Sequence);
        // When I order within the Task<Parent>, result becomes IOrderedEnumerable 
        // and I can't return it.

        return await result;
    }

推荐答案

您要返回的结果是有序的子级列表.那不是你想要的.而是对子项进行排序，然后返回父项:

The result you are trying to return is the ordered list of children. That's not what you want. Instead sort the children then return the parent:

public async Task<Parent> GetParent(int id)
{
    var parent = context.Parents
        .Include(p => p.Children)
        .SingleOrDefaultAsync(p => p.Id == id);

    parent.Result.Children = parent.Result.Children.OrderBy(c => c.Sequence).ToList();

    return await parent;
}

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