按Linq进行分组和求和

Question

我想用Linq获得每个客户的总订单金额，我知道我需要分组和求和。我只是成功地分组了，没有对每个订单的总金额求和。

var OrderByCustumer = new[] {
new { name = "cust1", order = 400 },
new { name = "cust1", order = 250 },
new { name = "cust1", order = 130 },
new { name = "cust2", order = 30 },
new { name = "cust3", order = 205}
};

var res= OrderByCustumer.GroupBy(x=>x.name).Select((x,y)=>new{
a=x.Key
});

foreach(var a in res){
Console.WriteLine(a);
}

.**
OutPut
a = cust1 
a = cust2 
a = cust3
** 

Answer 1

试试这个

var res = OrderByCustumer.GroupBy(x => x.name).Select(x => new {
a = x.Key,
sum = x.Sum(c => c.order)
});
foreach (var item in res)
{
Console.WriteLine($"{ item.a} - Sum = {item.sum}");
}