protected void GetDepartment()
{
// Populate form with existing department record
Int32 DepartmentID = Convert.ToInt32(Request.QueryString["DepartmentID"]);
using (comp2007Entities db = new comp2007Entities())
{
Department d = (from objS in db.Departments
where objS.DepartmentID == DepartmentID
select objS).FirstOrDefault();
if (d != null)
{
txtName.Text = d.Name;
txtBudget.Text = Convert.ToString(d.Budget);
}
// Populate Courses that belong to this department in table below form
var objE = (from c in db.Courses
join dept in db.Departments on c.DepartmentID equals dept.DepartmentID
where dept.DepartmentID == DepartmentID
select new { c.CourseID, c.Title, c.Credits });
pnlCourses.Visible = true;
grdCourses.DataSource = objE.ToList();
grdCourses.DataBind();
}
}
protected void GetStudent()
{
// Populate form with existing student record
Int32 StudentID = Convert.ToInt32(Request.QueryString["StudentID"]);
using (comp2007Entities db = new comp2007Entities())
{
Student s = (from objS in db.Students
where objS.StudentID == StudentID
select objS).FirstOrDefault();
if (s != null)
{
txtLastName.Text = s.LastName;
txtFirstName.Text = s.FirstMidName;
txtEnrollmentDate.Text = s.EnrollmentDate.ToString("yyyy-MM-dd");
}
//enrollments - this code goes in the same method that populates the student form but below the existing code that's already in GetStudent()
var objE = (from en in db.Enrollments
join c in db.Courses on en.CourseID equals c.CourseID
join d in db.Departments on c.DepartmentID equals d.DepartmentID
where en.StudentID == StudentID
select new { en.EnrollmentID, en.Grade, c.Title, d.Name});
pnlCourses.Visible = true;
grdCourses.DataSource = objE.ToList();
grdCourses.DataBind();
}
}
protected void btnSave_Click(object sender, EventArgs e)
{
// Use EF to connect to SQL Server
using (comp2007Entities db = new comp2007Entities())
{
// Use the Department Model to save the new record
Department d = new Department();
Int32 DepartmentID = 0;
// Check the QueryString for an ID so we can determine add / update
if (Request.QueryString["DepartmentID"] != null)
{
// Get the ID from the URL
DepartmentID = Convert.ToInt32(Request.QueryString["DepartmentID"]);
// Get the current student from the Enity Framework
d = (from objS in db.Departments
where objS.DepartmentID == DepartmentID
select objS).FirstOrDefault();
}
d.Name = txtName.Text;
d.Budget = Convert.ToDecimal(txtBudget.Text);
// Call add only if we have no department ID
if (DepartmentID == 0)
{
db.Departments.Add(d);
}
db.SaveChanges();
// Redirect to the updated departments page
Response.Redirect("departments.aspx");
}
}
protected void grdCourses_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
// Store which row was clicked
Int32 selectedRow = e.RowIndex;
// Get the selected CourseID using the grid's Data Key collection
Int32 CourseID = Convert.ToInt32(grdCourses.DataKeys[selectedRow].Values["CourseID"]);
// Use Enity Framework to remove the selected student from the DB
using (comp2007Entities db = new comp2007Entities())
{
// Check for enrollments in the course, and remove them. Otherwise, it'll throw a foreign key exception
foreach (Enrollment en in db.Enrollments)
{
if (en.CourseID == CourseID)
{
db.Enrollments.Remove(en);
}
}
Course c = (from objS in db.Courses
where objS.CourseID == CourseID
select objS).FirstOrDefault(); // Using First would get an error if no data comes back, FirstOrDefault won't throw an error
// Do the delete
db.Courses.Remove(c);
db.SaveChanges();
}
// Refresh the grid
GetCourses();
}
protected void GetCourses()
{
// Connect to EF
using (comp2007Entities db = new comp2007Entities())
{
String sortString = Session["SortColumn"].ToString() + " " + Session["SortDirection"].ToString();
// Query the Courses table, using the Enity Framework
var Courses = from c in db.Courses
select new { c.CourseID, c.Title, c.Credits, c.Department.Name };
grdCourses.DataSource = Courses.AsQueryable().OrderBy(sortString).ToList();
grdCourses.DataBind();
}
}
protected void GetStudents()
{
// Connect to EF
using (comp2007Entities db = new comp2007Entities())
{
String sortString = Session["SortColumn"].ToString() + " " + Session["SortDirection"].ToString();
// Query the Students table, using the Enity Framework
var Students = from s in db.Students
select s;
// Bind the result to the gridview
grdStudents.DataSource = Students.AsQueryable().OrderBy(sortString).ToList();
grdStudents.DataBind();
}
}
protected void btnSave_Click(object sender, EventArgs e)
{
// Use EF to connect to SQL Server
using (comp2007Entities db = new comp2007Entities())
{
// Use the Course Model to save the new record
Course c = new Course();
Int32 CourseID = 0;
Int32 DepartmentID = Convert.ToInt32(ddlDepartment.SelectedValue);
// Check the QueryString for an ID so we can determine add / update
if (Request.QueryString["CourseID"] != null)
{
// Get the ID from the URL
CourseID = Convert.ToInt32(Request.QueryString["CourseID"]);
// Get the current Course from the Enity Framework
c = (from objS in db.Courses
where objS.CourseID == CourseID
select objS).FirstOrDefault();
}
c.Title = txtTitle.Text;
c.Credits = Convert.ToInt32(txtCredits.Text);
c.DepartmentID = DepartmentID;
// Call add only if we have no Course ID
if (CourseID == 0)
{
db.Courses.Add(c);
}
db.SaveChanges();
// Redirect to the updated courses page
Response.Redirect("courses.aspx");
}
}
protected void btnAdd_Click(object sender, EventArgs e)
{
Int32 StudentID = Convert.ToInt32(ddlAddStudent.SelectedValue);
Int32 CourseID = Convert.ToInt32(Request.QueryString["CourseID"]);
Boolean alreadyExists = false;
Enrollment en = new Enrollment();
using (comp2007Entities db = new comp2007Entities())
{
// Loop through the enrollment table, and check to see if the student is already signed up for this course
foreach (Enrollment enroll in db.Enrollments)
{
if (enroll.StudentID == StudentID && enroll.CourseID == CourseID)
{
alreadyExists = true;
}
}
// If the enrollment doesn't exist, add the student to the course.
if (!alreadyExists)
{
en.StudentID = StudentID;
en.CourseID = CourseID;
db.Enrollments.Add(en);
db.SaveChanges();
warningLabel.Visible = false;
}
else
{
warningLabel.Visible = true;
}
}
GetCourse();
}
protected void btnSave_Click(object sender, EventArgs e)
{
// Use EF to connect to SQL Server
using (comp2007Entities db = new comp2007Entities())
{
// Use the Student Model to save the new record
Student s = new Student();
Int32 StudentID = 0;
// Check the QueryString for an ID so we can determine add / update
if (Request.QueryString["StudentID"] != null)
{
// Get the ID from the URL
StudentID = Convert.ToInt32(Request.QueryString["StudentID"]);
// Get the current student from the Enity Framework
s = (from objS in db.Students
where objS.StudentID == StudentID
select objS).FirstOrDefault();
}
s.LastName = txtLastName.Text;
s.FirstMidName = txtFirstName.Text;
s.EnrollmentDate = Convert.ToDateTime(txtEnrollmentDate.Text);
// Call add only if we have no student ID
if (StudentID == 0)
{
db.Students.Add(s);
}
db.SaveChanges();
// Redirect to the updated students page
Response.Redirect("students.aspx");
}
}
protected void grdCourses_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
Int32 CourseID = Convert.ToInt32(grdCourses.DataKeys[e.RowIndex].Values["CourseID"]);
using (comp2007Entities db = new comp2007Entities())
{
// Check for any enrollments in the course to be deleted, and remove them. Otherwise, it'll
// throw a foreign key exception
foreach (Enrollment en in db.Enrollments)
{
if (en.CourseID == CourseID)
{
db.Enrollments.Remove(en);
}
}
// Find the selected course
Course c = (from objS in db.Courses
where objS.CourseID == CourseID
select objS).FirstOrDefault(); // Using First would get an error if no data comes back, FirstOrDefault won't throw an error
// Do the delete
db.Courses.Remove(c);
db.SaveChanges();
//Refresh the data on the page
GetDepartment();
}
}
protected void grdDepartments_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
// Store which row was clicked
Int32 selectedRow = e.RowIndex;
// Get the selected DepartmentID using the grid's Data Key collection
Int32 DepartmentID = Convert.ToInt32(grdDepartments.DataKeys[selectedRow].Values["DepartmentID"]);
// Use Enity Framework to remove the selected student from the DB
using (comp2007Entities db = new comp2007Entities())
{
// Need to clear out any courses inside of Department, and need to clear out any enrollments inside of each course. Otherwise,
// i'll get a foreign key restraint error.
foreach (Course c in db.Courses)
{
if (c.DepartmentID == DepartmentID)
{
foreach (Enrollment en in db.Enrollments)
{
if (en.CourseID == c.CourseID)
{
db.Enrollments.Remove(en);
}
}
db.Courses.Remove(c);
}
}
Department d = (from objS in db.Departments
where objS.DepartmentID == DepartmentID
select objS).FirstOrDefault(); // Using First would get an error if no data comes back, FirstOrDefault won't throw an error
// Do the delete
db.Departments.Remove(d);
db.SaveChanges();
}
// Refresh the grid
GetDepartments();
}
protected void grdStudents_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
// Store which row was clicked
Int32 selectedRow = e.RowIndex;
// Get the selected StudentID using the grid's Data Key collection
Int32 StudentID = Convert.ToInt32(grdStudents.DataKeys[selectedRow].Values["StudentID"]);
// Use Enity Framework to remove the selected student from the DB
using (comp2007Entities db = new comp2007Entities())
{
Student s = (from objS in db.Students
where objS.StudentID == StudentID
select objS).FirstOrDefault(); // Using First would get an error if no data comes back, FirstOrDefault won't throw an error
// Do the delete
db.Students.Remove(s);
db.SaveChanges();
}
// Refresh the grid
GetStudents();
}
protected void GetCourse()
{
// Populate form with existing Course record
Int32 CourseID = Convert.ToInt32(Request.QueryString["CourseID"]);
using (comp2007Entities db = new comp2007Entities())
{
Course c = (from objS in db.Courses
where objS.CourseID == CourseID
select objS).FirstOrDefault();
Department selectedItem = (from objD in db.Departments
where c.DepartmentID == objD.DepartmentID
select objD).FirstOrDefault();
if (c != null)
{
txtTitle.Text = c.Title;
txtCredits.Text = Convert.ToString(c.Credits);
ddlDepartment.SelectedValue = selectedItem.DepartmentID.ToString();
}
//enrollments - This will show who is enrolled in the course
var objE = (from en in db.Enrollments
join st in db.Students on en.StudentID equals st.StudentID
where en.CourseID == CourseID
select new { en.EnrollmentID, st.StudentID, st.LastName, st.FirstMidName, st.EnrollmentDate });
pnlCourses.Visible = true;
grdStudents.DataSource = objE.ToList();
grdStudents.DataBind();
}
}
protected void Page_Load(object sender, EventArgs e)
{
// If save wasn't clicked AND we have a CourseID in the URL
if ((!IsPostBack))
{
using (comp2007Entities db = new comp2007Entities()) {
// Add available departments to a dropdown list
foreach (Department d in db.Departments)
{
ddlDepartment.Items.Add(new ListItem(d.Name, d.DepartmentID.ToString()));
}
}
if (Request.QueryString.Count > 0)
{
GetCourse();
using (comp2007Entities db = new comp2007Entities())
{
// Add available students to a drop down list
foreach (Student s in db.Students)
{
ddlAddStudent.Items.Add(new ListItem(s.LastName + ", " + s.FirstMidName, s.StudentID.ToString()));
}
}
}
}
}
protected void grdStudents_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
// Get the student's enrollment ID
Int32 EnrollmentID = Convert.ToInt32(grdStudents.DataKeys[e.RowIndex].Values["EnrollmentID"]);
using (comp2007Entities db = new comp2007Entities())
{
Enrollment objE = (from en in db.Enrollments
where en.EnrollmentID == EnrollmentID
select en).FirstOrDefault();
//Delete
db.Enrollments.Remove(objE);
db.SaveChanges();
//Refresh the data on the page
GetCourse();
}
}
