循环遍历列表并组合标识符相同的总计

Question

我当然有一个objetcs汽车列表其中的变量是:

使

模型

服务成本

让我们说清单填满了:

法拉利,F50,300

保时捷,911,700

丰田,Camary,300

保时捷,911,400

宝马,Z4,1200

保时捷,911,900

保时捷,356A,700

如您所见,我的列表包含保时捷911有服务费用的三条记录.

我如何遍历我的列表,找到重复的911并将它们组合成一个单独的记录？所以我最终得到:

法拉利,F50,300

保时捷,911,2000

丰田,Camary,300

宝马,Z4,1200

保时捷,356A,700

我到目前为止所做的事情是行不通的,因为我的记录可能最终会出现在错误的区域:

    List<Car> CombinedCarRecords = new List<Car>(CarDetailRecords); //Original list here being used
    List<Car> NormalList = new List<Car>();
    List<Car> NewList = new List<Car>();//Making new lists to keep the records in
    Car normalRecord = new Car();
    Car combinedRecord = new Car();//new objects to keep the values in and add the others
    string oldVal = "";
    string newVal = "";//used to find the same cars
    foreach (var item in CombinedCarRecords )
    {
        normalRecord = new ClaimDetailRecord();
        combinedRecord = new ClaimDetailRecord();
        oldVal = newVal;
        newVal = item.Model;
        if (oldVal == newVal)
        {
            combinedRecord = item;
            CombinedCarRecords.Add(combinedRecord);
        }
        else
        {
            normalRecord = item;
            NormalList.Add(normalRecord);
        }
    }//I think the way I try to find the records here is not working, as the old and new values will always be different, if maybe not for some records where they are right after each other. But there is still that initial one

    decimal totalP = 0;

    if (CombinedTariffsRecords.Count > 0)
    {
        foreach (var item in CombinedTariffsRecords)
        {
        }
    }
    else
        NewList = NormalList;
    //This is where I'm supposed to add up the totals, but I think my code before will render this code useless

总而言之,我尝试过,但我无法想出更好的方法来存储值并合并我的记录.

Answer 1

最简单的方法是使用LINQ Enumerable.GroupBy和Sum:

var newCarList = NormalList
   .GroupBy(c => new {  c.Make, c.Model })
   .Select(carGroup => new Car{ 
       Make = carGroup.Key.Make, 
       Model = carGroup.Key.Model,
       ServiceCost = carGroup.Sum(c => c.ServiceCost)
    })
   .ToList();