I am working on a hands-on question which my Company has given me as a part of my training. The hands-on is based on the Code-First Approach of Entity Framework Modelling. So I have created the course class as follows:
//Course.cs file
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Exercise1
{
public class Course
{
public int CourseId { get; set; }
public String CourseName { get; set; }
public double CourseFee { get; set; }
public int Duration { get; set; }
public String InstructorName { get; set; }
}
}
and then i have defined the CourseContext class as follows:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.Entity;
namespace Exercise1
{
public class CourseContext:DbContext
{
public CourseContext() : base("name=CourseConnectionString"){}
public DbSet<Course> Courses {get; set;}
//public virtual DbSet<Course> Courses {get; set;}
}
}
and then the CourseRepository class as follows:
using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
namespace Exercise1 //DO NOT Change the namespace name
{
public class CourseRepository //DO NOT Change the class name
{
//Thi perform operation like insert,update, retrieve and delete method.
private CourseContext context;
public CourseRepository(CourseContext context)
{
this.context=context;
//last line
}
public IList<Course> GetCourseList()
{
IList<Course> result = this.context.Courses.ToList();
return result;
//last line
}
public Course GetCourseByID(int courseId)
{
Course c = new Course();
c = null;
c = this.context.Courses.Find(courseId);
return c;
//Implement code here
}
public void InsertCourse(Course course)
{
this.context.Courses.Add(course);
this.context.SaveChanges();
Console.WriteLine("Details Added Successfully");
// last line
}
public Course UpdateCourseFee(int id, double fee)
{
Course c = new Course();
c = null;
foreach(Course cc in this.context.Courses)
{
if(cc.CourseId == id)
{
cc.CourseFee = fee;
c = cc;
}
}
this.context.SaveChanges();
return c;
}
}
}
and finally in the program.cs which is the main file i wrote the code as follows:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace Exercise1
{
public class Program
{
static void Main(string[] args)
{
CourseContext courseContext = new CourseContext();
CourseRepository cr = new CourseRepository(courseContext);
Course NewCourse = new Course();
// taking the details of the first course
Console.WriteLine("Enter Course Id");
NewCourse.CourseId = int.Parse(Console.ReadLine());
Console.WriteLine("Enter Course Name");
NewCourse.CourseName = Console.ReadLine();
Console.WriteLine("Enter Duration");
NewCourse.Duration = int.Parse(Console.ReadLine());
Console.WriteLine("Enter Course Fee");
NewCourse.CourseFee = double.Parse(Console.ReadLine());
Console.WriteLine("Enter Instructor Name");
NewCourse.InstructorName = Console.ReadLine();
cr.InsertCourse(NewCourse);
// get course list
var resultList = cr.GetCourseList();
foreach(var item in resultList)
{
Console.WriteLine("{0}",item);
}
// get course details by id
Console.WriteLine("get Course Details By id");
int id = int.Parse(Console.ReadLine());
var result = cr.GetCourseByID(id);
if(result != null)
{
Console.WriteLine(result);
}
//update the course Fee
Console.WriteLine("Update Course Fee");
int updateId = int.Parse(Console.ReadLine());
double fee = double.Parse(Console.ReadLine());
Course tush = cr.UpdateCourseFee(updateId,fee);
if(tush!=null)
{
Console.WriteLine("Updated Successfully");
}
}
}
}
**Now everytime i run the code of the tekstac console. I always get the error as follows: **
Failed TestCase Name : Test1InsertProduct Failure Message : System.NotSupportedException : Unsupported expression: m => m.CoursesNon-overridable members (here: CourseContext.get_Courses) may not be used in setup / verification expressions.
Failed TestCase Name : Test2GetCourseByID Failure Message : System.NotSupportedException : Unsupported expression: c => c.CoursesNon-overridable members (here: CourseContext.get_Courses) may not be used in setup / verification expressions.
Failed TestCase Name : Test3UpdateCourseFee Failure Message : System.NotSupportedException : Unsupported expression: c => c.CoursesNon-overridable members (here: CourseContext.get_Courses) may not be used in setup / verification expressions.
I really don't have any idea why is this happening.
But when i use the virtual keyword for the DbSet Courses as this 'public virtual DbSet Courses {get; set;}' , I Don't get any error. My instructor has also not told me anything about this.
Can anyone tell me what changes when i use the virtual keyword ? I really need your help.
