将系统集合列表<anonymous>转换为通用列表<myviewmodel> ASP.NET-MVC5

Question

我正在使用ASP.NET-MVC5应用程序。我有三个模型类，我需要传递模型从控制器到视图的数据，所以我使用view-Model类来组合所有三个类并尝试传递但是我收到错误，如屏幕截图所示。我需要方法“GetCourseByStudentID”

的帮助

从数据库中读取数据的Linq方法

 public List<StudentCourseSchoolAndCampusViewModel> GetCourseByStudentID(int _studentID)
    {
        try
        {
            using (var _uow = new StudentProfile_UnitOfWork())
            {
                var _record = (from _course in _uow.Course_Repository.GetAll()
                              join _school in _uow.School_Repository.GetAll() on _course.SchoolID equals _school.SchoolID
                              join _campus in _uow.Campus_Repository.GetAll() on _course.CampusID equals _campus.CampusID
                              where _course.StudentID == _studentID
                               select new { _course, _school, _campus }).ToList();


                return _record;
            }
        }
        catch { return null; }
    }

视图模型

public class StudentCourseSchoolAndCampusViewModel
{
    public StudentCourseSchoolAndCampusViewModel() { }

    public Course _courseModel { get; set; }
    public School _schoolModel { get; set; }
    public Campus _campusModel { get; set; }

}

控制器

 public ActionResult EditStudentCourse()
    {
        var _StudentCourseModel = _studentProfileServices.GetCourseByStudentID(6);

        return null; // incomplete 
    }

Answer 1

您可以使用Select方法生成实体类型列表：

    public List<StudentCourseSchoolAndCampusViewModel> GetCourseByStudentID(int _studentID)
    {
        try
        {
            using (var _uow = new StudentProfile_UnitOfWork())
            {
                var _record = (from _course in _uow.Course_Repository.GetAll()
                    join _school in _uow.School_Repository.GetAll() on _course.SchoolID equals _school.SchoolID
                    join _campus in _uow.Campus_Repository.GetAll() on _course.CampusID equals _campus.CampusID
                    where _course.StudentID == _studentID
                    select new { _course, _school, _campus }).ToList();


                var studentsVM = _record.Select(s=> new StudentCourseSchoolAndCampusViewModel()
                                          {
                                                 _courseModel = s._course, 
                                                 _schoolModel = s._school, 
                                                 _campusModel = s._campus
                                          }
                );

                return studentsVM;
            }
        }
        catch { return null; }
    } 

如果你想知道Select（Func选择器）是如何工作的 - 这是MSDN上的解释： https://msdn.microsoft.com/en-us/library/vstudio/bb548891(v=vs.100).aspx

Answer 2

//...
var _record = (from _course in _uow.Course_Repository.GetAll()
                join _school in _uow.School_Repository.GetAll() on _course.SchoolID equals _school.SchoolID
                join _campus in _uow.Campus_Repository.GetAll() on _course.CampusID equals _campus.CampusID
                where _course.StudentID == _studentID
                // Here is the problem, you have to specify the type.
                select new StudentCourseSchoolAndCampusViewModel { 
                           Course = _course, 
                           School = _school, 
                           Campus = _campus }).ToList();

我认为这将解决您的问题。

Answer 3

非常感谢Andriy指导...我有点改变并且决定发送视图模型类的模型而不是列表......

返回数据的功能

 public partial class StudentProfileServices
{
    #region Get Student Course By StudentID
    public StudentCourseSchoolAndCampusViewModel GetCourseByStudentID(int _studentID)
    {
        try
        {
            using (var _uow = new StudentProfile_UnitOfWork())
            {
                var _record = (from _course in _uow.Course_Repository.GetAll()
                              join _school in _uow.School_Repository.GetAll() on _course.SchoolID equals _school.SchoolID
                              join _campus in _uow.Campus_Repository.GetAll() on _course.CampusID equals _campus.CampusID
                              where _course.StudentID == _studentID
                              select new StudentCourseSchoolAndCampusViewModel  {_courseModel= _course, _schoolModel = _school, _campusModel = _campus }).FirstOrDefault();

                return _record;
            }
        }
        catch { return null; }
    }

控制器

   public ActionResult EditStudentCourse()
    {
        StudentCourseSchoolAndCampusViewModel _StudentCourseModel = new StudentCourseSchoolAndCampusViewModel();

       _StudentCourseModel = _studentProfileServices.GetCourseByStudentID(6);


        return PartialView("EditStudentCourse_Partial", _StudentCourseModel);
    }

视图

@model App.DAL.Model.StudentCourseSchoolAndCampusViewModel

<h1>edit student course</h1>

@Model._courseModel.ModeOfStudy  // to test the model data