如何对列表中同QuestionReference的QuestionScores对象属性求和？

首先修正你的QuestionScores类定义（原代码缺少class关键字）：

public class QuestionScores
{
    public string QuestionReference { get; set; }
    public int StudentScore { get; set; }
    public int QuestionScore { get; set; }
}

使用LINQ的GroupBy方法就能轻松实现按QuestionReference分组并求和的需求，代码示例如下：

using System.Linq;
using System.Collections.Generic;

// 初始化示例数据
var scoreList = new List<QuestionScores>
{
    new QuestionScores { QuestionReference = "U1C1", StudentScore = 1, QuestionScore = 4 },
    new QuestionScores { QuestionReference = "U1C1", StudentScore = 3, QuestionScore = 4 },
    new QuestionScores { QuestionReference = "U1C2", StudentScore = 2, QuestionScore = 4 }
};

// 分组合并逻辑
var mergedScores = scoreList
    .GroupBy(s => s.QuestionReference)
    .Select(g => new QuestionScores
    {
        QuestionReference = g.Key,
        StudentScore = g.Sum(s => s.StudentScore),
        QuestionScore = g.Sum(s => s.QuestionScore)
    })
    .ToList();

代码说明 #

• GroupBy(s => s.QuestionReference)：将列表按QuestionReference字段分组，相同引用的对象会被分到同一组中。
• Select(g => ...)：遍历每个分组，创建新的QuestionScores对象，其中：
  • g.Key就是分组对应的QuestionReference值；
  • g.Sum(s => s.StudentScore)对组内所有对象的StudentScore求和；
  • g.Sum(s => s.QuestionScore)对组内所有对象的QuestionScore求和。

执行上述代码后，mergedScores就是你想要的合并结果：

{ "U1C1", 4, 8 }
{ "U1C2", 2, 4 }

内容的提问来源于stack exchange，提问作者RWBrad