C#中多集合組合使用方法，主要用到 Enumerable.Join方法

var skuInfoList = new Dictionary<int, List<long>>();
                var ctParamList = new List<long>();
                foreach (var sku in skuList)
                {
                    var singleSku = sku.Split(‘|‘);
                    ctParamList 
 
= new List<long>();
                    foreach (var skuParam in skuParamList)
                    {
                        var singleSkuParam = skuParam.Split(‘:‘);
                        if (singleSku[0] == singleSkuParam[0])
                        {
                            var singleParam = singleSkuParam[1
 
].Split(‘|‘);
                            ctParamList.Add(Convert.ToInt64(singleParam[0]));
                        }
                    }
                    skuInfoList.Add(Convert.ToInt32(singleSku[0]), ctParamList);
                }
                var res = new List<List<long>>() { new
 
 List<long>() };
                Func<List<long>, List<List<long>>> func = lst =>
                {
                    return res.Join(lst, x => 1, x => 1, (x, y) =>
                    {
                        var tem = x.ToList();
                        tem.Add(y);
                        return tem;
                    }).ToList();
                };
                foreach (var skuInfo in skuInfoList)
                    res.AddRange(func(skuInfo.Value));

關鍵代碼：

var res = new List<List<long>>() { new List<long>() };
                Func<List<long>, List<List<long>>> func = lst =>
                {
                    return res.Join(lst, x => 1, x => 1, (x, y) =>
                    {
                        var tem = x.ToList();
                        tem.Add(y);
                        return tem;
                    }).ToList();
                };

C#中多集合組合實現