protected void btnSave_Click(object sender, EventArgs e)
        {
            //connect
            using (DefaultConnection db = new DefaultConnection())
            {
                //create new department in memory
                Department dep = new Department();

                //check url
                if (!String.IsNullOrEmpty(Request.QueryString["DepartmentID"]))
                {
                    Int32 DepartmentID = Convert.ToInt32(Request.QueryString["DepartmentID"]);

                    dep = (from d in db.Departments
                           where d.DepartmentID == DepartmentID
                           select d).FirstOrDefault();

                }
                //fill new properties of the new department
                dep.Name = txtName.Text;
                dep.Budget = Convert.ToDecimal(txtBudget.Text);

                //save the new department
                if (String.IsNullOrEmpty(Request.QueryString["DepartmentID"]))
                {
                    db.Departments.Add(dep);
                }
                db.Departments.Add(dep);
                db.SaveChanges();

                //redirect to department list page
                Response.Redirect("departments.aspx");
            }
        }
        protected void btnSave_Click(object sender, EventArgs e)
        {
            //connect
            using (DefaultConnection db = new DefaultConnection())
            {

                //create a new department in memory
                Department dep = new Department();

                // op2 :Int32 DepartmentID = 0;

                //check fot a url
                if (!String.IsNullOrEmpty(Request.QueryString["DepartmentID"]))
                {
                    Int32 DepartmentID = Convert.ToInt32(Request.QueryString["DepartmentID"]);
                    // op2: DepartmentID = Convert.ToInt32(Request.QueryString["DepartmentID"]);
                    dep = (from d in db.Departments
                           where d.DepartmentID == DepartmentID
                           select d).FirstOrDefault();
                }

                //fill the property of the new department
                dep.Name = txtname.Text;
                dep.Budget = Convert.ToDecimal(txtBudget.Text);

                //add if we have no id in the url
                if (String.IsNullOrEmpty(Request.QueryString["DepartmentID"]))
                {
                    db.Departments.Add(dep);
                }

                //op2: if(DepartmentID==0)

                // save the new department
                //excute the change commands
                db.SaveChanges();

                //redirect to the departments list page
                Response.Redirect("departments.aspx");

            }
        }