/// <summary>
/// Retrieves all the courses in the database and
/// populates the available courses listview
/// </summary>
public void PopulateAvailableCourses()
{
try
{
using (var context = new SchoolU_DBEntities())
{
AvailableCourseCollection.Clear();
IList <Course> allCourses = context.Courses.Where(i => i.CourseId != 0).ToList();
if (allCourses.Any())
{
foreach (var course in allCourses)
{
_availableCourseCollection.Add(course);
}
AvailableCourseCollection = _availableCourseCollection;
IsAddButtonEnabled = AvailableCourseCollection.Any();
IsRemoveButtonEnabled = AvailableCourseCollection.Any();
}
}
}
catch (Exception ex)
{
//MessageBox.Show(ex.Message);
return;
}
}
/// <summary>
/// Reset all the fields to
/// their default values
/// </summary>
public void ClearFields()
{
CourseName = string.Empty;
SelectedDepartment = DepartmentCollection.ElementAt(0);
SelectedCourseCollection.Clear();
AvailableCourseCollection.Clear();
PopulateAvailableCourses();
Edit_SaveLabel = "Edit";
IsEditEnabled = SelectedCourse != null;
}
/// <summary>
/// Populates the fields with the appropriate values
/// stored in the database for that selected course
/// </summary>
public void PopulateFieldsOnEdit()
{
Edit_SaveLabel = "Save";
try
{
if (SelectedCourse != null)
{
using (var context = new SchoolU_DBEntities())
{
// Gets the course object based on the selected Department Name
Course currentlySelectedCourse = context.Courses.Where(i => i.CourseName == SelectedCourse.CourseName).Single();
// Sets the Course name
CourseName = currentlySelectedCourse.CourseName;
// Gets the deparment name for the selected Course
string departmentName = context.Departments.Where(i => i.DepartmentId == currentlySelectedCourse.DepartmentId).Select(i => i.DepartmentName).Single();
// Selects the associated department for the course
SelectedDepartment = DepartmentCollection.Where(i => i.DepartmentName == departmentName).Single();
// Gets all the preReq Ids associated with the selected course
IList <int> preReqIds = (from c in context.Courses
join pr in context.PreRequisites on c.CourseId equals pr.CourseId
where c.CourseId == currentlySelectedCourse.CourseId
select pr.PrereqId).ToList();
if (preReqIds.Any())
{
// Gets the course name based on the Pre-req Id
IList <Course> course_Name = context.Courses.Where(i => preReqIds.Contains(i.CourseId)).ToList();
foreach (var item in course_Name)
{
if (AvailableCourseCollection.Where(i => i.CourseId == item.CourseId).Any())
{
// Had to remove item this way, because it expects the exact same object to be in the list, otherwise it won't remove it.
AvailableCourseCollection.Remove(AvailableCourseCollection.Where(i => i.CourseId == item.CourseId).Single());
}
SelectedCourseCollection.Add(item);
}
}
}
}
}
catch (Exception ex)
{
//MessageBox.Show(ex.Message);
return;
}
}
/// <summary>
/// Deletes the selected Course
/// </summary>
public void DeleteSelectedCourse()
{
try
{
using (var context = new SchoolU_DBEntities())
{
if (SelectedCourse != null)
{
// Removes the selected course from the Available courses list
// Then deletes it from the database
Course courseForDeletion = context.Courses.Where(i => i.CourseName == SelectedCourse.CourseName).Single();
context.Entry(courseForDeletion).State = EntityState.Deleted;
AvailableCourseCollection.Remove(courseForDeletion);
context.SaveChanges();
}
}
}
catch (Exception ex)
{
//MessageBox.Show(ex.Message);
return;
}
}