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 getStudents()
{
//conect and use database student table
using (DefaultConnection db = new DefaultConnection())
{
var stdt = from s in db.Students
select s;
//bind quuery return to grid
grdStudents.DataSource = stdt.ToList();
grdStudents.DataBind();
}
}
protected void getDepartment()
{
//look up the selected department and fill the form
using (DefaultConnection db = new DefaultConnection()){
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();
//prepopulate the for fields
txtName.Text = dep.Name;
txtbudget.Text = dep.Budget.ToString();
}
}
protected void grdStudents_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
//identify student id to manipulate
Int32 StudentID = Convert.ToInt32(grdStudents.DataKeys[e.RowIndex].Values["StudentID"]);
//Select current id based upon selected row
using (DefaultConnection db = new DefaultConnection()){
Student stdt = (from s in db.Students
where s.StudentID == StudentID
select s).FirstOrDefault();
db.Students.Remove(stdt);
db.SaveChanges();
//refresh grid
getStudents();
}
}
protected void getStudent()
{
//fill in form based upon selected student
using (DefaultConnection db = new DefaultConnection())
{
Int32 StudentID = Convert.ToInt32(Request.QueryString["StudentID"]);
//search departmet
Student stdt = (from s in db.Students
where s.StudentID == StudentID
select s).FirstOrDefault();
//populate fields
txtLName.Text = stdt.LastName;
txtFName.Text = stdt.FirstMidName;
}
}
protected void btnSave_Click(object sender, EventArgs e)
{
//connect to database
using (DefaultConnection db = new DefaultConnection())
{
//create new student in memory
Student stdt = new Student();
Int32 StudentID = 0;
DateTime EnDate = DateTime.Now;
//handle updating a record
if (!String.IsNullOrEmpty(Request.QueryString["StudentID"]))
{
StudentID = Convert.ToInt32(Request.QueryString["StudentID"]);
stdt = (from s in db.Students
where s.StudentID == StudentID
select s).FirstOrDefault();
//set eroll date to equal existing result
EnDate = stdt.EnrollmentDate;
}
//fill in student details
stdt.FirstMidName = txtLName.Text;
stdt.LastName = txtFName.Text;
//add current date time as time of registering
stdt.EnrollmentDate = EnDate;
if (StudentID == 0)
{
//create new row in database
db.Students.Add(stdt);
}
db.SaveChanges();
//redirect back to students page
Response.Redirect("students.aspx");
}
}
protected void grdDepartments_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
//identify department id to be deleted from the row the user selected
Int32 DepartmentID = Convert.ToInt32(grdDepartments.DataKeys[e.RowIndex].Values["DepartmentID"]);
//connect to database
using (DefaultConnection db = new DefaultConnection())
{
//SElect current department based upon id
Department dep = (from d in db.Departments
where d.DepartmentID == DepartmentID
select d).FirstOrDefault();
db.Departments.Remove(dep);
db.SaveChanges();
//refresh the grid
GetDepartments();
}
}
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;
//handle updating a recod
if (!String.IsNullOrEmpty(Request.QueryString["DepartmentID"]))
{
DepartmentID = Convert.ToInt32(Request.QueryString["DepartmentID"]);
dep = (from d in db.Departments
where d.DepartmentID == DepartmentID
select d).FirstOrDefault();
}
//fill the properties of the department
dep.Name = txtName.Text;
dep.Budget = Convert.ToDecimal(txtbudget.Text);
if (DepartmentID == 0)
{
//save the new department
db.Departments.Add(dep);
}
db.SaveChanges();
//redirect to departments list page
Response.Redirect("departments.aspx");
}
}
