protected void btnSave_Click(object sender, EventArgs e)
{
try
{
//use EG 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 EF
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);
}
//run the update or insert
db.SaveChanges();
//redirect
Response.Redirect("students.aspx");
}
}
catch (Exception err)
{
Server.Transfer("/error.aspx");
}
}
protected void GetStudent()
{
//populate form wih existing student record
Int32 StudentID = Convert.ToInt32(Request.QueryString["StudentID"]);
try
{
//connect to db via EF
using (comp2007Entities db = new comp2007Entities())
{
Student s = (from objs in db.Students
where objs.StudentID == StudentID
select objs).FirstOrDefault();
//map the student properties to the form controls
txtLastName.Text = s.LastName;
txtFirstMidName.Text = s.FirstMidName;
txtEnrollmentDate.Text = s.EnrollmentDate.ToShortDateString();
//map the student properties to the form controls if we found a match
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 err)
{
Server.Transfer("/error.aspx");
}
}
protected void btnSave_Click(object sender, EventArgs e)
{
try
{
//use EG to connect to SQL Server
using (comp2007Entities db = new comp2007Entities())
{
//use the Student Model to save the new record
//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 EF
s = (from objs in db.Departments
where objs.DepartmentID == DepartmentID
select objs).FirstOrDefault();
}
s.Name = txtDepartmentName.Text;
s.Budget = Convert.ToDecimal(txtBudget.Text);
//call add only if we have no student ID
if (DepartmentID == 0)
{
db.Departments.Add(s);
}
db.SaveChanges();
//redirect
Response.Redirect("departments.aspx");
}
}
catch (Exception err)
{
Server.Transfer("/error.aspx");
}
}
protected void GetDepartments()
{
//populate form wih existing student record
Int32 DepartmentID = Convert.ToInt32(Request.QueryString["DepartmentID"]);
try
{
//connect to db via EF
using (comp2007Entities db = new comp2007Entities())
{
Department s = (from objs in db.Departments
where objs.DepartmentID == DepartmentID
select objs).FirstOrDefault();
//map the student properties to the form controls
txtDepartmentName.Text = s.Name;
txtBudget.Text = s.Budget.ToString();
//map the student properties to the form controls if we found a match
if (s != null)
{
txtDepartmentName.Text = s.Name;
txtBudget.Text = s.Budget.ToString();
}
//courses - this code goes in the same method that populates the student form but below the existing code that's already in GetDepartments()
var objE = (from c in db.Courses
join d in db.Departments on c.DepartmentID equals d.DepartmentID
where c.DepartmentID == DepartmentID
select new { c.DepartmentID, c.Title, c.Credits });
grdCourses.DataSource = objE.ToList();
grdCourses.DataBind();
}
}
catch (Exception err)
{
Server.Transfer("/error.aspx");
}
}
protected void GetCourses()
{
try
{
//connect to EF
using (comp2007Entities db = new comp2007Entities())
{
String SortString = Session["SortColumn"].ToString() + " " + Session["SortDirection"].ToString();
//query the students table using EF and LINQ
var Courses = from s in db.Courses
select new { s.CourseID, s.Title, s.Credits, s.Department.Name };
//bind the result to the gridview
grdCourses.DataSource = Courses.AsQueryable().OrderBy(SortString).ToList();
grdCourses.DataBind();
}
}
catch (Exception err)
{
Server.Transfer("/error.aspx");
}
}
protected void GetStudents()
{
try
{
//connect to EF
using (comp2007Entities db = new comp2007Entities())
{
String SortString = Session["SortColumn"].ToString() + " " + Session["SortDirection"].ToString();
//query the students table using EF and LINQ
var Students = from s in db.Students
select new { s.StudentID, s.LastName, s.FirstMidName, s.EnrollmentDate };
//bind the result to the gridview
grdStudents.DataSource = Students.AsQueryable().OrderBy(SortString).ToList();
grdStudents.DataBind();
}
}
catch (Exception err)
{
Server.Transfer("/error.aspx");
}
}
protected void grdCourses_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
//get selected record id
Int32 EnrollmentID = Convert.ToInt32(grdCourses.DataKeys[e.RowIndex].Values["EnrollmentID"]);
try
{
using (comp2007Entities db = new comp2007Entities())
{
//get selected record
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
GetDepartments();
}
}
catch (Exception err)
{
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 EF to remove the selected student from the db
using (comp2007Entities db = new comp2007Entities())
{
Course s = (from objs in db.Courses
where objs.CourseID == CourseID
select objs).FirstOrDefault();
//do the delete
db.Courses.Remove(s);
db.SaveChanges();
}
//refresh the grid
GetCourses();
}
catch (Exception err)
{
Server.Transfer("/error.aspx");
}
}