c# - 无法在 asp mvc 中隐式转换类型 'System.Collections.Generic.List

Question

我需要使用 Linq 加入 4 个表格。但它告诉我这个错误:

Error 1 Cannot implicitly convert type 'System.Collections.Generic.List<>' to 'System.Collections.Generic.List' E:\MyProject\GoKhoda\GoKhoda\Areas\Classes\StudentsFunc.cs 20 20 GoKhoda

这是我的代码:

public List<Tbl_Students> ShowAllStudents()
    {
        var qstudent = from s in _db.Tbl_Students
                       join pr in _db.Tbl_Pye_Reshte on s.StudentID equals pr.StudentID
                       join r in _db.Tbl_Reshte on pr.ReshteID equals r.ReshteID
                       join p in _db.Tbl_Paye on pr.PayeID equals p.PayeID
                       orderby p.PayeID descending
                       select new { StudentName = s.StudentName, StudentFamily = s.StudentFamily, StudentImage = s.StudentImage, StudentPayeName = p.PayeName, StudentReshtName = r.ReshteName };
        return qstudent.ToList();
    }

为什么要显示错误？我该如何解决这个问题？

Answer 1

使用这个:

var qstudent = from s in _db.Tbl_Students
    join pr in _db.Tbl_Pye_Reshte on s.StudentID equals pr.StudentID
    join r in _db.Tbl_Reshte on pr.ReshteID equals r.ReshteID
    join p in _db.Tbl_Paye on pr.PayeID equals p.PayeID
    orderby p.PayeID descending
    select new Tbl_Students { StudentName = s.StudentName, StudentFamily = s.StudentFamily, StudentImage = s.StudentImage, StudentPayeName = p.PayeName, StudentReshtName = r.ReshteName };
return qstudent.ToList();

Select new { ... }只会创建一个匿名类型，它不能转换为任何 除了object .

顺便说一句:您应该考虑根据应用程序中的实体来命名您的类型，在您的示例中为 Student ，而不是存储实体的表。