Question

我正在尝试将以下查询返回到字符串数组：

select top 10 c_initials, MAX(c_score) as MaxScore
from t_bisGame 
group by c_initials order by MaxScore desc

[WebMethod]
public string[] GetMyGameList()
{  
   //LINQ  
}

我一直在遇到：

无法隐式转换类型＆＃39; AnonymousType＃1 []＆＃39;到＆＃39; string []＆＃39;

使用以下代码

var employees = from e in db.t_bisGames
                group e by e.c_Initials into egrp
                let max = egrp.Max(scor => scor.c_Score)
                select new
                {

                    Name = egrp.First(val => val.c_Score == max).c_Initials.ToArray(),
                    Score = egrp.First(val => val.c_Score == max).c_Score.ToString().ToArray()
                };

Answer 1

问题是您的查询返回2个项目，而不仅仅是字符串。您的LINQ可能也是这样做的，并返回包含首字母和MaxScore作为属性的匿名类型。

您可以通过最后的第二个映射操作（Select）将其转换为字符串数组：

public string[] GetMyGameList()
{
     var query = db.BisGame.GroupBy(bg => bg.Initials)
              .Take(10)
              .Select(g => new { Initial = g.Key, MaxScore = g.Max(bg => bg.Score) });

     // Convert to string[] somehow, ie:
     return query.AsEnumerable().Select(i => string.Format("{0}:{1}", i.Initial, i.MaxScore)).ToArray();
}

如何使用max和group by将tsql转换为linq并返回String []

1 个答案: