LINQ的使用

汇总列表中各物品的数量

var list = (from t in lst
group t by t.SparePartNo into g
select new { g.Key, sum = g.Sum(p => p.SparePartQty), Total = g.Count() }).ToList();

查找每个类别中单价高于该类别平均单价的产品：

var categories =
    from p in db.Products
    group p by p.CategoryID into g
    select new {
        g.Key, 
        ExpensiveProducts =
            from p2 in g
            where p2.UnitPrice > g.Average(p3 => p3.UnitPrice)
            select p2
    };