public static void GenerateStudents()
{
Course course1 = new Course()
{
CourseName = "Entity Framework", Credits = 50
};
Course course2 = new Course()
{
CourseName = ".NET Framework", Credits = 50
};
Course course3 = new Course()
{
CourseName = "Javascript", Credits = 50
};
Course course4 = new Course()
{
CourseName = "Basic Algorithms", Credits = 50
};
Course course5 = new Course()
{
CourseName = "Http", Credits = 100
};
Course course6 = new Course()
{
CourseName = "Security Management", Credits = 50
};
Enrollment LWEF001 = new Enrollment()
{
Course = course1, EnrollmentName = "EF2398lw", Grade = "A-F", status = EnrollmentStatus.Approved
};
Enrollment LWNET01 = new Enrollment()
{
Course = course2, EnrollmentName = "NET294lw", Grade = "A-F", status = EnrollmentStatus.Waiting
};
Enrollment LWJS01 = new Enrollment()
{
Course = course3, EnrollmentName = "JS233lw", Grade = "A-F", status = EnrollmentStatus.Approved
};
Enrollment LWBA01 = new Enrollment()
{
Course = course4, EnrollmentName = "BA23864lw", Grade = "A-F", status = EnrollmentStatus.Approved
};
Enrollment IPEF001 = new Enrollment()
{
Course = course1, EnrollmentName = "EF2398ip", Grade = "A-F", status = EnrollmentStatus.Waiting
};
Enrollment IPNET01 = new Enrollment()
{
Course = course2, EnrollmentName = "NET294ip", Grade = "A-F", status = EnrollmentStatus.Waiting
};
Enrollment IPJS01 = new Enrollment()
{
Course = course3, EnrollmentName = "JS233ip", Grade = "A-F", status = EnrollmentStatus.Waiting
};
Enrollment IPBA01 = new Enrollment()
{
Course = course4, EnrollmentName = "BA23864ip", Grade = "A-F", status = EnrollmentStatus.Waiting
};
Enrollment JBHP01 = new Enrollment()
{
Course = course5, EnrollmentName = "HP23864jb", Grade = "A-F", status = EnrollmentStatus.Approved
};
Enrollment JBSM01 = new Enrollment()
{
Course = course6, EnrollmentName = "SM23864jb", Grade = "A-F", status = EnrollmentStatus.Approved
};
Student student1 = new Student()
{
FirstMidName = "Ivan",
LastName = "Prgomet",
EnrollmentDate = new DateTime(2015, 12, 24),
Enrollments = new HashSet <Enrollment>()
{
IPEF001, IPNET01, IPJS01, IPBA01
}
};
Student student2 = new Student()
{
FirstMidName = "Lea",
LastName = "Winchester",
EnrollmentDate = new DateTime(2015, 12, 24),
Enrollments = new HashSet <Enrollment>()
{
LWEF001, LWNET01, LWJS01, LWBA01
}
};
Student student3 = new Student()
{
FirstMidName = "Jason",
LastName = "Bourne",
EnrollmentDate = new DateTime(2015, 12, 24),
Enrollments = new HashSet <Enrollment>()
{
JBHP01, JBSM01
}
};
using (EducationContext context = new EducationContext())
{
context.Students.Add(student3);
context.Students.Add(student2);
context.Students.Add(student1);
context.Database.Log = Console.WriteLine;
context.SaveChanges();
}
}
static void Main(string[] args)
{
Database.SetInitializer(new DropCreateDatabaseAlways <EducationContext>());
GenerateStudents();
#region explanation 01
/*
* the code below doesnt have any include methods or entry loads.
* to work, the code below requires lazy loading. this means set the
* navigation properties in the relevant classes to virtual. when they are
* virtual, you should also not have any initialization of code in the constructors.
* If you dont have the navigation properties set to virtual, and you have the
* navigation properties initialized in the constructor, the code will not chrash,
* but it also wont display any data.
*
* setting the lazyloadingenabled property to false is just another way of
* removing all the virtual keyword from the navigation properties in the classes.
* it will crash. but if you have lazyloadingenabled property to false, and the
* navigation properties to virtual, one way to avoid a crash is to also initialize the
* properties in the constructor, which will dodge the nullreference exception.
*/
#endregion
#region code 01
//using (EducationContext context = new EducationContext())
//{
// //context.Configuration.LazyLoadingEnabled = false;
// foreach (var student in context.Students)
// {
// Console.WriteLine(student.FirstMidName + " " + student.LastName + "\nEnrolled to: ");
// foreach (var enrollment in student.Enrollments)
// {
// Console.WriteLine("\t" + enrollment.EnrollmentID + ": " + enrollment.EnrollmentName + " " + enrollment.Grade+" " +enrollment.status);
// Console.WriteLine("\t" + enrollment.Course.CourseID + ": " + enrollment.Course.CourseName + " (" + enrollment.Course.Credits + "p) ");
// Console.WriteLine();
// }
// Console.WriteLine("......................");
// Console.WriteLine();
// }
//}
#endregion
#region explanation 02
/*
* the code below has got includes for all the associated data for a student, so in the classes, no
* virtual keyword is required for the navigation properties. No initialization is required neither, but wont
* make any diference if you initialize the navigation properties in the constructor.
*/
#endregion
#region code 02
using (EducationContext context = new EducationContext())
{
foreach (var student in context.Students.Include(e => e.Enrollments.Select(c => c.Course)).ToList())
{
Console.WriteLine(student.FirstMidName + " " + student.LastName + "\nEnrolled to: ");
foreach (var enrollment in student.Enrollments)
{
Console.ForegroundColor = ReturnEnrollmentStatusColor(enrollment);
Console.WriteLine("\t" + enrollment.EnrollmentID + ": " + enrollment.EnrollmentName + " " + enrollment.Grade + " " + enrollment.status);
Console.WriteLine("\t" + enrollment.Course.CourseID + ": " + enrollment.Course.CourseName + " (" + enrollment.Course.Credits + "p) ");
Console.WriteLine();
Console.ResetColor();
}
Console.WriteLine("......................");
Console.WriteLine();
}
}
#endregion
}
