Linq挑战:将这段代码从方法链转换为标准Linq

挑战是如何从方法链转换到标准linq,这是一段充满group-by的代码。

上下文

Linq: rebuild hierarchical data from the flattened list

多亏了@Akash Kava,我找到了解决问题的方法。

链法公式

var macroTabs = flattenedList
        .GroupBy(x => x.IDMacroTab)
        .Select((x) => new MacroTab
        {
            IDMacroTab = x.Key,
            Tabs = x.GroupBy(t => t.IDTab)
                    .Select(tx => new Tab {
                        IDTab = tx.Key,
                        Slots = tx.Select(s => new Slot {
                           IDSlot = s.IDSlot
                     }).ToList()
            }).ToList()
        }).ToList();

发生的事情与此类似。。

var antiflatten = flattenedList
    .GroupBy(x => x.IDMacroTab)
    .Select(grouping => new MacroTab
    {
        IDMacroTab = grouping.Key,
        Tabs = (from t in grouping
                group grouping by t.IDTab
                into group_tx
                select new Tab
                {
                    IDTab = group_tx.Key,
                    Slots = (from s in group_tx
                    from s1 in s    
                    select new Slot
                    {
                        IDSlot = s1.IDSlot
                    }).ToList()
                }).ToList()
    });

LinqPad中的结果

https://dotnetfiddle.net/8mF1qI