Question

相关模型;

public class category_trans
{
    [Key]
    [Column(Order = 1)]
    public int category_id { get; set; }
    [Key]
    [Column(Order = 2)]
    public int language_id { get; set; }
    public string name { get; set; }
}

目前Linq查询，工作：

IQueryable<category_trans> APC =
            from ct in db.category_trans
            from c in db.Categories
            from l in db.ISO_Languages
            where (
            ct.category_id == c.ID 
            && ct.language_id == l.ID 
            && l.code.Substring(0,2) == culture
            && c.IsDeleted == false)
            select ct;

我想对查询结果进行分组，以便得到不同的category_trans.name（现在我得到了多个）。

尝试

IQueryable<category_trans> APC =
            from ct in db.category_trans
            from c in db.Categories
            from l in db.ISO_Languages
            where (
            ct.category_id == c.ID 
            && ct.language_id == l.ID 
            && l.code.Substring(0,2) == culture
            && c.IsDeleted == false)
            group ct by ct.name into g
            select new
            {
                category_id = g.category_id,
                name = g.name
            };

给我g.category_id和g.name

的错误

IGrouping <string,category_trans> does not contain a definition for 'category_id'...

为什么分组似乎失去对模型成员的引用以及如何修复它？

Answer 1

由于组可以包含多个，因此您可以使用Key属性作为名称：

IQueryable<category_trans> APC =
        from ct in db.category_trans
        from c in db.Categories
        from l in db.ISO_Languages
        where (
        ct.category_id == c.ID 
        && ct.language_id == l.ID 
        && l.code.Substring(0,2) == culture
        && c.IsDeleted == false)
        group ct by ct.name into g
        select new
        {
            category_id = g.First().category_id,
            name = g.Key
        };

我使用First来获取第一个category_id，您可能想要使用不同的逻辑。

强类型linq group by

1 个答案: