/// <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>
/// Check if the list of pre-requisites is different in any way
/// If so, then returns true
/// </summary>
/// <returns></returns>
public bool IsPreReqListDifferent()
{
try
{
using (var context = new SchoolU_DBEntities())
{
// Gets the course object based on the selected Department Name
Course currentlySelectedCourse = context.Courses.Where(i => i.CourseName == CourseName).Single();
// Variable to keep track of difference in pre-req list
bool isDifferent = true;
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();
if (SelectedCourseCollection.Count() == preReqIds.Count())
{
foreach (var item in course_Name)
{
// IsDifferent is set to false when the list hasn't changed at all
if (SelectedCourseCollection.Where(i => i.CourseId == item.CourseId).Any())
{
isDifferent = false;
}
// IsDifferent is set to true when the list is different in one or more ways
else
{
return(true);
}
}
}
}
return(isDifferent);
}
}
catch (Exception ex)
{
//MessageBox.Show(ex.Message);
return(false);
}
}
/// <summary>
/// Commits the courses, that were moved to the
/// pre-reqs listview, to the preReqs table
/// </summary>
public void CommitPreReqs()
{
try
{
using (var context = new SchoolU_DBEntities())
{
// Gets all the courses names
IList <string> allCourseName = context.Courses.Where(i => i.CourseId != 0).Select(i => i.CourseName).ToList();
// Gets the course id for the course that was recently added
int courseAdded = context.Courses.Where(i => i.CourseName == CourseName).Select(i => i.CourseId).Single();
if (SelectedCourseCollection.Any())
{
// Stores the PreRequisite objects so they can be added all at the same time using the AddRange method
IList <PreRequisite> PreReqList = new List <PreRequisite>();
if (IsPreReqListDifferent())
{
for (int i = 0; i < GetPreReqIds().Count; i++)
{
var newPreReq = new PreRequisite()
{
CourseId = courseAdded,
PrereqId = GetPreReqIds().ElementAt(i)
};
PreReqList.Add(newPreReq);
}
context.PreRequisites.AddRange(PreReqList);
}
context.SaveChanges();
}
}
}
catch (Exception ex)
{
//MessageBox.Show(ex.Message);
return;
}
}
/// <summary>
/// Gets a list of course Ids based on the pre-req names
/// currently in the pre-reqs list (SelectedCourseCollection)
/// </summary>
/// <returns></returns>
public IList <int> GetPreReqIds()
{
IList <int> preReqIds = new List <int>();
try
{
using (var context = new SchoolU_DBEntities())
{
if (SelectedCourseCollection.Any())
{
// Gets all the pre-req courses names
IList <string> pre_reqNames = SelectedCourseCollection.Where(i => i.CourseName != string.Empty).Select(i => i.CourseName).ToList();
// Gets all the course ids off of the courses names added to the pre-reqs list // pre-req = course ids
return(preReqIds = context.Courses.Where(i => pre_reqNames.Contains(i.CourseName)).Select(i => i.CourseId).ToList());
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
return(null);
}
return(null);
}
/// <summary>
/// Checks if the course in edit is added
/// as it's own pre-requisite
/// </summary>
/// <returns></returns>
public bool IsCourseItsOwnPreRequisite()
{
return(GetPreReqIds().Contains(SelectedCourseCollection.Where(i => i.CourseName == CourseName).Select(i => i.CourseId).SingleOrDefault()));
}
