Linq return null on 'false' where clausule

本文关键字：where clausule false return Linq null on | 更新日期: 2023-09-27 17:59:08

我有一个类似的查询：

var solution = (from hit2 in Hits.Where(x => x.Combination.Count == 2)
                where IsPossibleHit(hit2, 2, currentSymbols)
                from hit3 in Hits.Where(x => x.Combination.Count == 3)
                where IsPossibleHit(hit3, 3, currentSymbols)
                from hit4 in Hits.Where(x => x.Combination.Count == 4)
                where IsPossibleHit(hit4, 4, currentSymbols)
                from hit5 in Hits.Where(x => x.Combination.Count == 5)
                where IsPossibleHit(hit5, 5, currentSymbols)
                select new
                {
                    hitsList = new List<Hit>(){
                     hit2,
                     hit3,
                     hit4,
                     hit5}
                }).ToList();

我的问题是，在创建组时，如果hit2和hit3是可能的命中，我需要创建新对象，但是，因为hit4返回false，所以整个组合被丢弃。

如何做到这一点？

编辑：我想我没有弄清楚我需要什么，或者我的问题是什么：

我的问题是，当IsPossibleHit（hitN）返回false时，整个组合将被丢弃（由linq），但我需要的是无论如何都要创建对象，返回false的命中设置为null，甚至不添加到新对象的命中列表中。

Linq return null on 'false' where clausule

var solution = (from hit2 in Hits.Where(x => x.Combination.Count == 2)
                where IsPossibleHit(hit2, 2, currentSymbols)
                let h3 = from hit3 in Hits.Where(x => x.Combination.Count == 3)
                            where IsPossibleHit(hit3, 3, currentSymbols)
                let h4 = from hit4 in Hits.Where(x => x.Combination.Count == 4)
                            where IsPossibleHit(hit4, 4, currentSymbols)
                let h5 = from hit5 in Hits.Where(x => x.Combination.Count == 5)
                            where IsPossibleHit(hit5, 5, currentSymbols)
                select new
                {
                    hitsList = new List<Hit>(){
                     hit2,
                     h3,
                     h4,
                     h5}
                }).ToList();

试试这样的东西。请检查语法，因为我还没有运行或编译它。

我想你想做的是：

var res = Hits.Where(h => h.Combination.Count >= 2
                       && h.Combination.Count <= 5
                       && IsPossibleHit(h, h.Combination.Count, currentSymbols)
               ).ToList();

您想按点击数分组，并只保留每组中可能的点击数吗？先用Where过滤，然后用GroupBy:过滤

var groupedHits = from h in Hits
                  where h.Combination.Count >= 2 && h.Combination.Count <= 5
                  where IsPossibleHit(h, h.Combination.Count, currentSymbols)
                  group h by h.Combination.Count
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