protected void btnUpdate_Click(object sender, EventArgs e)
        {
            int teacherID = Convert.ToInt32(lblTID.Text);

            ctx = new TeacherInformationDataContext();

            TeacherInformation teacher = new TeacherInformation();

            teacher = ctx.TeacherInformations.Single(x => x.TeacherID == teacherID);

            teacher.TeacherName = txtName.Text;
            teacher.Email       = txtEmail.Text;
            teacher.Phone       = txtMobile.Text;
            teacher.DOB         = Convert.ToDateTime(txtDOB.Text);
            teacher.Course      = ddlCourse.SelectedValue;
            teacher.Address     = txtAddress.Text;


            ctx.SubmitChanges();

            ShowAlert("Data Updated Successfully!!");
            this.DataLoad();
            ClearData();


            //=============
        }
        protected void btnDelete_Click(object sender, EventArgs e)
        {
            int teacerId = Convert.ToInt32(lblTID.Text);

            using (ctx = new TeacherInformationDataContext())
            {
                TeacherInformation teacher = (from c in ctx.TeacherInformations
                                              where c.TeacherID == teacerId
                                              select c).FirstOrDefault();
                ctx.TeacherInformations.DeleteOnSubmit(teacher);
                ctx.SubmitChanges();
            }
            ShowAlert("Data Deleted Successfully!!");
            this.DataLoad();
            ClearData();
        }
        protected void btnAdd_Click(object sender, EventArgs e)
        {
            using (ctx = new TeacherInformationDataContext())
            {
                TeacherInformation teacher = new TeacherInformation
                {
                    TeacherName = txtName.Text,
                    Email       = txtEmail.Text,
                    Phone       = txtMobile.Text,
                    DOB         = Convert.ToDateTime(txtDOB.Text),
                    Course      = ddlCourse.SelectedValue,
                    Address     = txtAddress.Text
                };
                ctx.TeacherInformations.InsertOnSubmit(teacher);
                ctx.SubmitChanges();
            }

            ShowAlert("Data Inserted Successfully!!");
            this.DataLoad();

            ClearData();
        }