private void EnrollButton_Click(object sender, EventArgs e)
{
Student student = (Student)this.StudentListBox.SelectedItem;
Course course = (Course)this.CourseListBox.SelectedItem;
try
{
using (var db = new CoursemoDataContext())
{
var TxOptions = new System.Transactions.TransactionOptions();
TxOptions.IsolationLevel = System.Transactions.IsolationLevel.Serializable;
using (var Tx = new System.Transactions.TransactionScope(System.Transactions.TransactionScopeOption.Required, TxOptions))
{
var queryEnroll = from en in db.Enrolleds
where en.CRN == course.CRN && en.Active == true
select en;
System.Threading.Thread.Sleep(timeInMs);
//int count = 0;
bool studentFound = false;
int priorityKey = 0;
foreach (Enrolled en in queryEnroll)
{
//count++;
if (en.NetID == student.NetID)
{
studentFound = true;
}
priorityKey = en.Priority;
}
if (studentFound)
{
MessageBox.Show("Student is already enrolled");
return;
}
//else, check numbers
if (queryEnroll.Count() < course.ClassSize)
{
//can be enrolled
priorityKey++;
Enrolled enroll = new Enrolled();
//enroll.Priority = priorityKey;
enroll.CRN = course.CRN;
enroll.NetID = student.NetID;
enroll.Active = true;
db.Enrolleds.InsertOnSubmit(enroll);
db.SubmitChanges();
Tx.Complete();
MessageBox.Show("Enrolled: " + enroll.NetID + " into " + enroll.CRN);
//return;
}
else
{
//class full, go to wait list
var queryWait = from w in db.Waitlists
where w.CRN == course.CRN && w.Active == true && w.NetID == student.NetID
select w;
//if already on waitlist
if (queryWait.Any())
{
MessageBox.Show("Already on waitlist");
return;
}
//Adding to waitlist
else
{
foreach (Waitlist w in queryWait)
{
w.Priority = priorityKey;
}
priorityKey++;
Waitlist wait = new Waitlist();
//wait.Priority = priorityKey;
wait.CRN = course.CRN;
wait.NetID = student.NetID;
wait.Active = true;
db.Waitlists.InsertOnSubmit(wait);
db.SubmitChanges();
Tx.Complete();
MessageBox.Show("Adding to waitlist: " + wait.NetID + " for " + wait.CRN);
}
}//end else
//MessageBox.Show("Should not reach here...");
//db.SubmitChanges();
//Tx.Complete();
} //Using tx
} //Using db
}
catch (Exception ex)
{
MessageBox.Show("Enroll failed: " + ex.Message);
}
finally
{
StudentListBox_SelectedIndexChanged(sender, e);
CourseListBox_SelectedIndexChanged(sender, e);
//course list
}
}//end enroll button
private void DropButton_Click(object sender, EventArgs e)
{
Student student = (Student)this.StudentListBox.SelectedItem;
Course course = (Course)this.CourseListBox.SelectedItem;
try
{
using (var db = new CoursemoDataContext())
{
var TxOptions = new System.Transactions.TransactionOptions();
TxOptions.IsolationLevel = System.Transactions.IsolationLevel.Serializable;
using (var Tx = new System.Transactions.TransactionScope(System.Transactions.TransactionScopeOption.Required, TxOptions))
{
var queryEnroll = from en in db.Enrolleds
where en.CRN == course.CRN && en.NetID == student.NetID && en.Active == true
select en;
System.Threading.Thread.Sleep(timeInMs);
//if found to be enrolled
if (queryEnroll.Any())
{
foreach (Enrolled en in queryEnroll)
{
en.Active = false;
}
//next, put waitlist individual in class
Waitlist temp;
var queryWait = from w in db.Waitlists
where w.CRN == course.CRN && w.Active == true
select w;
temp = queryWait.First();
Enrolled enroll = new Enrolled();
enroll.CRN = course.CRN;
enroll.NetID = temp.NetID;
enroll.Active = true;
db.Enrolleds.InsertOnSubmit(enroll);
queryWait.First().Active = false;
db.SubmitChanges();
Tx.Complete();
MessageBox.Show("Dropped: " + student.NetID + " from " + course.CRN);
}//end to be enrolled block
//else drop from waitlist
else
{
var queryWait = from w in db.Waitlists
where w.CRN == course.CRN && w.NetID == student.NetID && w.Active == true
select w;
if (queryWait.Any())
{
foreach (Waitlist w in queryWait)
{
w.Active = false;
}
db.SubmitChanges();
Tx.Complete();
MessageBox.Show("Dropped: " + student.NetID + " from waitlist for " + course.CRN);
}
else
{
MessageBox.Show("Invalid, student not enrolled in class nor on waitlist");
}
}
//MessageBox.Show("Should not reach here...");
//db.SubmitChanges();
//Tx.Complete();
} //Using tx
} //Using db
}
catch (Exception ex)
{
MessageBox.Show("Enroll failed: " + ex.Message);
}
finally
{
StudentListBox_SelectedIndexChanged(sender, e);
CourseListBox_SelectedIndexChanged(sender, e);
//course list
}
}
private void detach_Enrolleds(Enrolled entity)
{
this.SendPropertyChanging();
entity.Student = null;
}
private void attach_Enrolleds(Enrolled entity)
{
this.SendPropertyChanging();
entity.Student = this;
}
partial void DeleteEnrolled(Enrolled instance);
partial void UpdateEnrolled(Enrolled instance);
partial void InsertEnrolled(Enrolled instance);
