protected void SaveButton_Click(object sender, EventArgs e)
{
// Use EF to connect to the server
using (DefaultConn db = new DefaultConn()) {
// use the Student model to create a new student object and
// save a new record
Student newStudent = new Student();
int StudentID = 0;
if (Request.QueryString.Count > 0) // our URL has a StudentID in it
{
// get the id from the URL
StudentID = Convert.ToInt32(Request.QueryString["StudentID"]);
// get the current student from EF DB
newStudent = (from student in db.Students
where student.StudentID == StudentID
select student).FirstOrDefault();
}
// add form data to the new student record
newStudent.LastName = LastNameTextBox.Text;
newStudent.FirstMidName = FirstNameTextBox.Text;
newStudent.EnrollmentDate = Convert.ToDateTime(EnrollmentDateTextBox.Text);
// use LINQ to ADO.NET to add / insert new student into the database
if (StudentID == 0)
{
db.Students.Add(newStudent);
}
// save our changes - also updates and inserts
db.SaveChanges();
// Redirect back to the updated students page
Response.Redirect("~/Students.aspx");
}
}
/**
* <summary>
* This method is used to detelte student records from the database using ef
* </summary>
*
* @method StudentsGridView_RowDeleting
* @param {object} sender
* @param {GridViewDeleteEventArgs} e
* @return {void}
*/
protected void StudentsGridView_RowDeleting(object sender, GridViewDeleteEventArgs e)
{
// store which row was selected for deletion
int selectedRow = e.RowIndex;
// get the selected StudentID using the grid's Datakey collection
int StudentID = Convert.ToInt32(StudentsGridView.DataKeys[selectedRow].Values["StudentID"]);
// use EF to find the selected student from DB and Remove it
using (DefaultConn db = new DefaultConn()) {
Student deletedStudent = (from studentRecords in db.Students
where studentRecords.StudentID == StudentID
select studentRecords).FirstOrDefault();
// remove the student record from the database
db.Students.Remove(deletedStudent);
// save changes to the db
db.SaveChanges();
// refresh the grid
this.GetStudents();
}
}
