Question

你好我有这样的linq查询：

var data = from d in db.DailyBonus
                   where d.Date>= startDate1 && d.Date<=endDate1
                   group d by new { Em = d.Employee.Id } into g
                   select new BasisViewModel
                   {
                       EmployeeId = g.Key.Em,
                       EmployeeNumber = g.FirstOrDefault().Employee.EmployeeNumber,
                       FullName = g.FirstOrDefault().Employee.FullName,
                       HK1 = (decimal)g.FirstOrDefault().ManDays,
                       Basis1 = (decimal)g.FirstOrDefault().BonusBase,
                       HK2 = (
                              (from d in db.DailyBonus 
                              where d.Date>= startDate2 && d.Date<=endDate2
                              group d by new { Em = d.Employee.Id } into g2
                              select new 
                              {
                                 Mandays =  g.FirstOrDefault().ManDays <-- this is decimal type
                              }
                             ),
                   };

问题是，我只想为HK2选择一条记录并在子查询中分配给Mandays但是下面有一个错误：

无法隐式转换类型＆＃39; System.Linq.IQueryable＆＃39;到十进制＆＃39;

解决方案是什么？谢谢

Answer 1

而不是返回匿名类（function show_user($data){ $this->db->where('pkid', $data); $query = $this->db->get('users'); $query_result = $query->result(); return $query_result; } function show($data){ $this->db->select('*'); $this->db->from('users'); $this->db->where('pkid', $data); $query = $this->db->get(); $result = $query->result(); return $result; } // Update Query For Selected Student function update_user($id,$data){ $this->db->where('pkid', $id); $this->db->update('users', $data); }）

new {...}

返回您想要的select new { Mandays = g.FirstOrDefault().ManDays <-- this is decimal type }：

Decimal

Answer 2

您应该在最后添加另一个FirstOrDefault()并使用简单值而不是匿名类型：

var data = from d in db.DailyBonus
                       where d.Date>= startDate1 && d.Date<=endDate1
                       group d by new { Em = d.Employee.Id } into g
                       select new BasisViewModel
                       {
                           EmployeeId = g.Key.Em,
                           EmployeeNumber = g.FirstOrDefault().Employee.EmployeeNumber,
                           FullName = g.FirstOrDefault().Employee.FullName,
                           HK1 = (decimal)g.FirstOrDefault().ManDays,
                           Basis1 = (decimal)g.FirstOrDefault().BonusBase,
                           HK2 = (
                                  (from d in db.DailyBonus 
                                  where d.Date>= startDate2 && d.Date<=endDate2
                                  group d by new { Em = d.Employee.Id } into g2
                                  select g.FirstOrDefault().ManDays <-- this is simple value now

                                 ).FirstOrDefault(),<--this is another first or default 
                       };

无法隐式转换类型System.Linq.IQueryable <anonymoustype＃6>＆＃39;到十进制＆＃39;

2 个答案: