private void cmdDrop2_Click(object sender, EventArgs e)
{
if (lstStuCourses2.SelectedIndex > -1)
{
//Code for Delay
int timeInMS;
if (System.Int32.TryParse(this.txtDelay.Text, out timeInMS) == true)
{
;
}
else
{
timeInMS = 0;
}
System.Threading.Thread.Sleep(timeInMS);
int retries = 0;
while (retries < 3)
{
try
{
using (var transaction = db.Database.BeginTransaction())
{
Student stu = lstStudents2.SelectedItem as Student;
Course toDrop = lstStuCourses2.SelectedItem as Course;
if (toDrop == null)
{
string courseString = lstStuCourses2.SelectedItem as String;
string[] val = courseString.Split(' ');
//MessageBox.Show(val[2]);
int crnLookup = Convert.ToInt32(val[2]);
toDrop = db.Courses.Single <Course>(c => c.CRN == crnLookup);
}
if (db.StudentCourses.Any <StudentCourse>(sc => sc.NetID == stu.NetID && sc.CRN == toDrop.CRN))
{
var c = db.Courses.Find(toDrop.CRN);
c.NumEnrolled--;
db.StudentCourses.Remove(db.StudentCourses.Single <StudentCourse>(sc => sc.CRN == toDrop.CRN && stu.NetID == sc.NetID));
db.SaveChanges();
MessageBox.Show(stu.NetID + " has successfully dropped " + toDrop.Department + " " + toDrop.CourseNum + "!");
if (db.Waitlists.Any <Waitlist>(w => w.CRN == toDrop.CRN))
{
Waitlist nextStudent = db.Waitlists.First <Waitlist>(w => w.CRN == toDrop.CRN);
var stuCourseObj = new StudentCourse {
CRN = nextStudent.CRN, NetID = nextStudent.NetID
};
db.StudentCourses.Add(stuCourseObj);
c.NumEnrolled++;
db.Waitlists.Remove(nextStudent);
db.SaveChanges();
MessageBox.Show(nextStudent.NetID + " has been enrolled in " + toDrop.Department + " " + toDrop.CourseNum + " from the waitlist!");
}
}
else if (db.Waitlists.Any <Waitlist>(w => w.NetID == stu.NetID && w.CRN == toDrop.CRN))
{
db.Waitlists.Remove(db.Waitlists.First <Waitlist>(w => w.CRN == toDrop.CRN && stu.NetID == w.NetID));
db.SaveChanges();
MessageBox.Show(stu.NetID + " has successfully ben removed from the waitlist for " + toDrop.Department + " " + Convert.ToString(toDrop.CourseNum) + "!");
}
else
{
MessageBox.Show("Error student is neither enrolled, nor on the waitlist for this course!");
}
transaction.Commit();
break;
}//end transaction
}
catch (SqlException ex)
{
if (ex.Number == 1205)
{
retries++;
}
else
{
MessageBox.Show(ex.Message);
break;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
break;
}
finally
{
cmdLoadCourses_Click(sender, e);
cmdLoadStudents_Click(sender, e);
}
}
}
else if (lstStuCourses2.Items.Count == 0)
{
MessageBox.Show("You currently have no courses to drop!");
}
else
{
MessageBox.Show("Please select a course to add from the respective list of student courses.");
}
}
private void cmdEnroll2_Click(object sender, EventArgs e)
{
if (lstCourses.SelectedIndex > -1)
{
//Code for Delay
int timeInMS;
if (System.Int32.TryParse(this.txtDelay.Text, out timeInMS) == true)
{
;
}
else
{
timeInMS = 0;
}
System.Threading.Thread.Sleep(timeInMS);
int retries = 0;
while (retries < 3)
{
try
{
using (var transaction = db.Database.BeginTransaction())
{
//db = new SampleContext();
Course cur = lstCourses.SelectedItem as Course;
Student stu = lstStudents2.SelectedItem as Student;
if (db.StudentCourses.Any <StudentCourse>(sc => sc.NetID == stu.NetID && sc.CRN == cur.CRN))
{
MessageBox.Show("Student is already enrolled in this course!");
}
else if (cur.NumEnrolled == cur.ClassSize)
{
//Add student to the waitlist
var waitlistObj = new Waitlist {
CRN = cur.CRN, NetID = stu.NetID
};
db.Waitlists.Add(waitlistObj);
db.SaveChanges();
MessageBox.Show("This course is currently at capacity, you have been added to the Waitlist");
}
else
{
//Add student to the course enrollments.
string num = Convert.ToString(cur.CourseNum);
var stuCourseObj = new StudentCourse {
CRN = cur.CRN, NetID = stu.NetID
};
db.StudentCourses.Add(stuCourseObj);
var c = db.Courses.Find(cur.CRN);
c.NumEnrolled++;
db.SaveChanges();
MessageBox.Show("You have been added to the course " + cur.Department + " " + num + "!");
}
transaction.Commit();
break;
}//end transaction
}
catch (SqlException ex)
{
if (ex.Number == 1205)
{
retries++;
}
else
{
MessageBox.Show(ex.Message);
break;
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
break;
}
finally
{
cmdLoadCourses_Click(sender, e);
cmdLoadStudents_Click(sender, e);
}
}
}
else
{
MessageBox.Show("Please select a course to add from the list at the left");
}
}
