c# - "select new"和 "Select(a => new"的区别

请考虑这 2 个查询及其结果:

var result = ent.tblCustomGroupBies
            .GroupBy(a => groupA.Contains(a.Group.Value) ? "A" :
                          groupB.Contains(a.Group.Value) ? "B" :
                          "N/a")
            .Select(a => new
            {
                KEY = a.Key,
                VALUE = a.Count()
            });

它的结果是 GridView::

第二个查询:

 var result3 = from p in ent.tblCustomGroupBies
               group p by new { Criterion = groupA.Contains(p.Group.Value) ? "A" :
                                            groupB.Contains(p.Group.Value) ? "B" :
                                            "N/a" }
               into g
               select new { KEY = g.Key, VALUE = g.Count() };

它的结果是 GridView::

为什么第一个查询中的 Select(a => new) 显示键列但 select new 没有显示？

最佳答案

试试这个

var result3 = from p in ent.tblCustomGroupBies
               group p by new { Criterion = groupA.Contains(p.Group.Value) ? "A" :
                                            groupB.Contains(p.Group.Value) ? "B" :
                                            "N/a" }
               into g
               select new { KEY = g.Key.Criterion, VALUE = g.Count() };

关于c# - "select new"和 "Select(a => new"的区别，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/13283365/