protected void GetDepartment()
{
//populate form with existing student record
Int32 DepartmentID = Convert.ToInt32(Request.QueryString["DepartmentID"]);
try
{
//connect to db using entity framework
using (comp2007Entities db = new comp2007Entities())
{
//populate a student instance with the studentID from the URL paramater
Department d = (from objS in db.Departments
where objS.DepartmentID == DepartmentID
select objS).FirstOrDefault();
//map the student properties to the form controls if we found a record
txtDeptName.Text = d.Name;
txtBudget.Text = d.Budget.ToString();
//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 c in db.Courses
join de in db.Departments on c.DepartmentID equals DepartmentID
where c.DepartmentID == DepartmentID
select new { c.CourseID, c.Title, c.Credits });
grdDepartment.DataSource = objE.ToList();
grdDepartment.DataBind();
}
}
catch (Exception)
{
Server.Transfer("/error.aspx");
}
}
protected void btnSave_Click(object sender, EventArgs e)
{
try
{
//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 query string 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 Entity Framework
s = (from objS in db.Students
where objS.StudentID == StudentID
select objS).FirstOrDefault();
}
s.LastName = txtLastName.Text;
s.FirstMidName = txtFirstMidName.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");
}
}
catch (Exception)
{
Server.Transfer("/error.aspx");
}
}
protected void btnSave_Click(object sender, EventArgs e)
{
try
{
//use EF to connect to SQL server
using (comp2007Entities db = new comp2007Entities())
{
//use the student model to save the new record
Department d = new Department();
Int32 DepartmentID = 0;
//check the query string 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 Entity Framework
d = (from objS in db.Departments
where objS.DepartmentID == DepartmentID
select objS).FirstOrDefault();
}
d.Name = txtDeptName.Text;
d.Budget = Convert.ToDecimal(txtBudget.Text);
//call add only if we have no student ID
if (DepartmentID == 0)
db.Departments.Add(d);
db.SaveChanges();
//redirect to the updated students page
Response.Redirect("departments.aspx");
}
}
catch (Exception)
{
Server.Transfer("/error.aspx");
}
}
protected void GetStudent()
{
//populate form with existing student record
Int32 StudentID = Convert.ToInt32(Request.QueryString["StudentID"]);
try
{
//connect to db using entity framework
using (comp2007Entities db = new comp2007Entities())
{
//populate a student instance with the studentID from the URL paramater
Student s = (from objS in db.Students
where objS.StudentID == StudentID
select objS).FirstOrDefault();
//map the student properties to the form controls if we found a record
if (s != null)
{
txtLastName.Text = s.LastName;
txtFirstMidName.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 });
grdCourses.DataSource = objE.ToList();
grdCourses.DataBind();
}
}
catch (Exception)
{
Server.Transfer("/error.aspx");
}
}
protected void GetCourses()
{
try
{
using (comp2007Entities db = new comp2007Entities())
{
String SortString = Session["SortColumn"].ToString() + " " + Session["SortDirection"].ToString();
//query the students table using EF and LINQ
var courses = from c in db.Courses
select c;
//bind he result to the gridview
grdCourses.DataSource = courses.AsQueryable().OrderBy(SortString).ToList();
grdCourses.DataBind();
}
}
catch (Exception)
{
Server.Transfer("/error.aspx");
}
}
protected void grdDepartment_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
//get the selected studentID using the grid's data key collection
Int32 CourseID = Convert.ToInt32(grdDepartment.DataKeys[e.RowIndex].Values["CourseID"]);
try
{
//use Entity Framework to remove the selected student from the db
using (comp2007Entities db = new comp2007Entities())
{
var objE = from en in db.Enrollments
where en.CourseID == CourseID
select en;
//do the delete
foreach (var enrollments in objE)
{
db.Enrollments.Remove(enrollments);
}
db.SaveChanges();
Course objC = (from c in db.Courses
where c.CourseID == CourseID
select c).FirstOrDefault();
//do the delete
db.Courses.Remove(objC);
db.SaveChanges();
}
}
catch (Exception)
{
Server.Transfer("/error.aspx");
}
//refresh the grid
GetDepartment();
}
protected void grdCourses_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
//get the selected studentID using the grid's data key collection
Int32 EnrollmentID = Convert.ToInt32(grdCourses.DataKeys[e.RowIndex].Values["EnrollmentID"]);
try
{
//use Entity Framework to remove the selected student from the db
using (comp2007Entities db = new comp2007Entities())
{
Enrollment objE = (from en in db.Enrollments
where en.EnrollmentID == EnrollmentID
select en).FirstOrDefault();
//do the delete
db.Enrollments.Remove(objE);
db.SaveChanges();
}
//refresh the grid
GetStudent();
}
catch (Exception)
{
Server.Transfer("/error.aspx");
}
}
protected void grdCourses_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 CourseID = Convert.ToInt32(grdCourses.DataKeys[selectedRow].Values["CourseID"]);
try
{
//use Entity Framework to remove the selected student from the db
using (comp2007Entities db = new comp2007Entities())
{
Course c = (from objS in db.Courses
where objS.CourseID == CourseID
select objS).FirstOrDefault();
//do the delete
db.Courses.Remove(c);
db.SaveChanges();
}
}
catch (Exception)
{
Server.Transfer("/error.aspx");
}
//refresh the grid
GetCourses();
}
