c# Linq 延迟执行挑战 - 创建 3 个不同列表所需的帮助

Question

我正在尝试从 2 个现有列表(A、B)创建 3 个不同的列表(1、2、3)。
这 3 个列表需要确定以下关系。

• 列表 1 - 列表 A 中但不在列表 B 中的项目
• 列表 2 - 列表 B 中但不在列表 A 中的项目
• 列表 3 - 两个列表中的项目。

然后我想将所有列表合并为一个列表。

我的问题是我想通过添加一个枚举来识别差异，该枚举识别每个列表的项目之间的关系。但是通过添加 Enum，Except Linq 函数无法识别(显然)列表相同的事实。因为 Linq 查询不同，所以我无法通过更改语句的顺序来解决这个问题，即。识别列表，然后添加枚举。

这是我必须的代码(不能正常工作)
可能有更好的方法。

        List<ManufactorListItem> manufactorItemList =
           manufactorRepository.GetManufactorList();

        // Get the Manufactors from the Families repository
        List<ManufactorListItem> familyManufactorList =
            this.familyRepository.GetManufactorList(familyGuid);

        // Identify Manufactors that are only found in the Manufactor Repository
        List<ManufactorListItem> inManufactorsOnly =
            manufactorItemList.Except(familyManufactorList).ToList();

        // Mark them as (Parent Only)
        foreach (ManufactorListItem manOnly in inManufactorsOnly) {
            manOnly.InheritanceState = EnumInheritanceState.InParent;
        }

        // Identify Manufactors that are only found in the Family Repository
        List<ManufactorListItem> inFamiliesOnly =
            familyManufactorList.Except(manufactorItemList).ToList();

        // Mark them as (Child Only)
        foreach (ManufactorListItem famOnly in inFamiliesOnly) {
            famOnly.InheritanceState = EnumInheritanceState.InChild;
        }

        // Identify Manufactors that are found in both Repositories
        List<ManufactorListItem> sameList =
            manufactorItemList.Intersect(familyManufactorList).ToList();

        // Mark them Accordingly
        foreach (ManufactorListItem same in sameList) {
            same.InheritanceState = EnumInheritanceState.InBoth;
        }

        // Create an output List
        List<ManufactorListItem> manufactors = new List<ManufactorListItem>();

        // Join all of the lists together.
        manufactors = sameList.Union(inManufactorsOnly).
            Union(inFamiliesOnly).ToList();

有什么想法可以解决这个问题吗？ 提前致谢

Answer 1

你可以让它更简单:

List<ManufactorListItem> manufactorItemList = ...;
List<ManufactorListItem> familyManufactorList = ...;
var allItems = manufactorItemList.ToDictionary(i => i, i => InheritanceState.InParent);

foreach (var familyManufactor in familyManufactorList)
{
    allItems[familyManufactor] = allItems.ContainsKey(familyManufactor) ?
                                 InheritanceState.InBoth : 
                                 InheritanceState.InChild;
}

//that's all, now we can get any subset items:  

var inFamiliesOnly = allItems.Where(p => p.Value == InheritanceState.InChild).Select(p => p.Key);
var inManufactorsOnly = allItems.Where(p => p.Value == InheritanceState.InParent).Select(p => p.Key);
var allManufactors = allItems.Keys;