protected void GetCourse()
{
//connect
using (DefaultConnection db = new DefaultConnection())
{
//get the selected courseid from url
Int32 CourseID = Convert.ToInt32(Request.QueryString["CourseID"]);
//query the db
Course objC = (from c in db.Courses
where c.CourseID == CourseID
select c).FirstOrDefault();
// populate the form
txtTitle.Text = objC.Title;
txtCredits.Text = objC.Credits.ToString();
ddlDepartment.SelectedValue = objC.DepartmentID.ToString();
//populate student enrollments grid
var Enrollments = from en in db.Enrollments
where en.CourseID == CourseID
orderby en.Student.LastName,
en.Student.FirstMidName
select en;
//bind to the grid
grdEnrollments.DataSource = Enrollments.ToList();
grdEnrollments.DataBind();
}
}
protected void GetStudent()
{
//look up selected student and fill form
using (DefaultConnection db = new DefaultConnection())
{
//store id from the url in a variable
Int32 StudentID = Convert.ToInt32(Request.QueryString["StudentID"]);
//look up student
Student stud = (from s in db.Students
where s.StudentID == StudentID
select s).FirstOrDefault();
//populate form fields
txtLast.Text = stud.LastName;
txtFirst.Text = stud.FirstMidName;
txtEnroll.Text = stud.EnrollmentDate.ToString();
//populate all courses student is enrolled in
var objK = (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});
grdCourses.DataSource = objK.ToList();
grdCourses.DataBind();
}
}
protected void GetCourses()
{
using (DefaultConnection db = new DefaultConnection())
{
var Courses = from c in db.Courses
select c;
grdCourses.DataSource = Courses.ToList();
grdCourses.DataBind();
}
}
protected void GetStudents()
{
//use enity framework to connect to get list of students
using (DefaultConnection db = new DefaultConnection())
{
var stud = from s in db.Students
select s;
//bind stud query results to our grid
grdStudents.DataSource = stud.ToList();
grdStudents.DataBind();
}
}
protected void GetDepartments()
{
//use Entity Framework to connect and get the list of Departments
using (DefaultConnection db = new DefaultConnection())
{
var deps = from d in db.Departments
select d;
//bind the deps query result to our grid
grdDepartments.DataSource = deps.ToList();
grdDepartments.DataBind();
}
}
protected void GetDepartment()
{
//look up the selected department and fill the form
using (DefaultConnection db = new DefaultConnection())
{
//store the id from the url in a variable
Int32 DepartmentID = Convert.ToInt32(Request.QueryString["DepartmentID"]);
//look up the department
Department dep = (from d in db.Departments
where d.DepartmentID == DepartmentID
select d).FirstOrDefault();
//pre-populate the form fields
txtName.Text = dep.Name;
txtBudget.Text = dep.Budget.ToString();
}
}
protected void GetDepartments()
{
//connect
using (DefaultConnection db = new DefaultConnection())
{
//get department list
var Departments = from d in db.Departments
orderby d.Name
select d;
//bind dropdown list
ddlDepartment.DataSource = Departments.ToList();
ddlDepartment.DataBind();
//add default option for dropdown after it's filled
ListItem DefaultItem = new ListItem("-Select-", "0");
ddlDepartment.Items.Insert(0, DefaultItem);
}
}
protected void btnSave_Click(object sender, EventArgs e)
{
//connect
using (DefaultConnection db = new DefaultConnection())
{
//create new course and fill properties
Course objC = new Course();
objC.Title = txtTitle.Text;
objC.Credits = Convert.ToInt32(txtCredits.Text);
objC.DepartmentID = Convert.ToInt32(ddlDepartment.SelectedValue);
//save
db.Courses.Add(objC);
db.SaveChanges();
//redirect
Response.Redirect("courses.aspx");
}
}
protected void btnSave_Click(object sender, EventArgs e)
{
using (DefaultConnection db = new DefaultConnection())
{
//create a new student in memory
Student stud = new Student();
Int32 StudentID = 0;
//check for url
if (!String.IsNullOrEmpty(Request.QueryString["StudentID"]))
{
//get id from url
StudentID = Convert.ToInt32(Request.QueryString["StudentID"]);
//look up the student
stud = (from s in db.Students
where s.StudentID == StudentID
select s).FirstOrDefault();
}
//fill the properties of the new student
stud.LastName = txtLast.Text;
stud.FirstMidName = txtFirst.Text;
stud.EnrollmentDate = Convert.ToDateTime(txtEnroll.Text);
//add if we have no id in the url
if (StudentID == 0)
{
db.Students.Add(stud);
}
//save the student
db.SaveChanges();
//redirect to student list page
Response.Redirect("students.aspx");
}
}
protected void grdDepartments_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
//identify the DepartmentID to be deleted from the row the user selected
Int32 DepartmentID = Convert.ToInt32(grdDepartments.DataKeys[e.RowIndex].Values["DepartmentID"]);
//connect
using (DefaultConnection db = new DefaultConnection())
{
Department dep = (from d in db.Departments
where d.DepartmentID == DepartmentID
select d).FirstOrDefault();
//delete
db.Departments.Remove(dep);
db.SaveChanges();
//refresh grid
GetDepartments();
}
}
protected void grdStudents_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
//identify id of student to delete from the row the user has chosen
Int32 StudentID = Convert.ToInt32(grdStudents.DataKeys[e.RowIndex].Values["StudentID"]);
//connect
using (DefaultConnection db = new DefaultConnection())
{
Student stud = (from s in db.Students
where s.StudentID == StudentID
select s).FirstOrDefault();
//delete
db.Students.Remove(stud);
db.SaveChanges();
//refresh grid
Response.Redirect("students.aspx");
}
}
protected void btnSave_Click(object sender, EventArgs e)
{
//connect
using (DefaultConnection db = new DefaultConnection())
{
//create a new department in memory
Department dep = new Department();
Int32 DepartmentID = 0;
//check for a url
if (!String.IsNullOrEmpty(Request.QueryString["DepartmentID"]))
{
//get the id from the url
DepartmentID = Convert.ToInt32(Request.QueryString["DepartmentID"]);
//look up the department
dep = (from d in db.Departments
where d.DepartmentID == DepartmentID
select d).FirstOrDefault();
}
//fill the properties of the new department
dep.Name = txtName.Text;
dep.Budget = Convert.ToDecimal(txtBudget.Text);
//add if we have no id in the url
if (DepartmentID == 0)
{
db.Departments.Add(dep);
}
//save the new department
db.SaveChanges();
//redirect to the departments list page
Response.Redirect("departments.aspx");
}
}
protected void grdCourses_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
//get selected id
Int32 EnrollmentID = Convert.ToInt32(grdCourses.DataKeys[e.RowIndex].Values["EnrollmentID"]);
//connect
using (DefaultConnection db = new DefaultConnection())
{
//get record
Enrollment objK = (from en in db.Enrollments
where en.EnrollmentID == EnrollmentID
select en).FirstOrDefault();
//delete
db.Enrollments.Remove(objK);
db.SaveChanges();
//refresh
GetStudent();
}
}
