Linq 用和分组数据

我有以下清单：

 mat.Add(new Material() { ID = 1, ProdName = "Cylinder", Weight=23, Discontinued='N'  });
 mat.Add(new Material() { ID = 2, ProdName = "Gas", Weight = 25, Discontinued='N' });
mat.Add(new Material() { ID = 3, ProdName = "Match", Weight = 23, Discontinued='N' });

我希望结果如下：

2 Products have Weight 23 and Discontinued N
1 Product have Weigth 25 Discontinued N

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现在还不清楚你到底是根据什么进行分组的——是重量还是中止状态？如果是这样，您只需执行以下操作：

var query = mat.GroupBy(material => 
                        new { material.Weight, material.Discontinued });

foreach (var result in query)
{
    Console.WriteLine("{0} products have {1}", result.Count(), result.Key);
}

明白了

.GroupBy(re => new { re.Weight, re.Discontinued })
           .Select(grp => new { CXXX = group.Key, Count = grp.Count()

“刚”组（按重量计算）停止

比如：

---

var result=mat.GroupBy（a=>new{a.Weight，a.contracted}）。选择（b=>new b.Key.Weight，b.Key.contracted，Count=b.Count（）}）

展示一下你的尝试如何？如果你能保持与问题中相同的属性，那会有所帮助。首先，这与求和有什么关系（根据你的标题）？