计算我的ASP.NET MVC项目中不同部门的相同产品名称的总和

Question

这可以从不同的城市组织汽车状态吗？我想使用LINQ（使用查询或方法语法）计算同一车名的汽车总数。我的表名“Cars”看起来像下图：我认为我已经有问题如何创建viewmodel并获得部门名称....然后制定LINQ代码...

试图这样做，但错误的结果：我试图做以下但是给我错误的结果

    public class Car
    {
        public int Id { get; set; }
        public string CarName { get; set; } 
        public int DeptId { get; set; }
        public int Status { get; set; }
    }

    public class Department
    {
        public int DeptId { get; set; }
        public string DeptName { get; set; }

    }

    public class CarViewModel
    {
        public string CarName { get; set; } ??? // Is this right?
        public Department DeptName { get; set; }
        public int Status { get; set; }
    }




 [HttpGet]
        public async Task<ActionResult> GetTotalCars()
        {
            using (context)
            {

                 var summary = (from c in context.Cars
                  group c by new { c.CarName, c.DeptId } into grp
                  join d in context.Departments on grp.Key.DeptId equals d.Id
                  select new CarViewModel { CarName = grp.Key.CarName, 
                                            DeptName =  d.DeptName, 
                                            Status = grp.Sum(s => s.Status) })
        .ToListAsync();

                return await summary;

            }

        }

如果你们能帮助我，我将不胜感激。

Answer 1

根据您的视图模型提示，您可以通过以下方式获取每个车名和每个部门的总计数：

 var summary = (from c in Cars
                  group c by new { c.CarName, c.DeptId } into grp
                  join d in Departments on grp.Key.DeptId equals d.Id
                  select new CarViewModel { CarName = grp.Key.CarName, 
                                            DeptName =  d.DeptName, 
                                            Status = grp.Sum(s => s.Status) })
                .ToList();