protected void btnSave_Click(object sender, EventArgs e)
        {
            var coursesID = Request.QueryString["ID"];

            if (coursesID == null)
            {
                Contoso.Models.Courses courses = new Contoso.Models.Courses();
                courses.Title        = txtTitle.Text;
                courses.Credits      = Convert.ToInt32(txtCredits.Text);
                courses.DepartmentID = Convert.ToInt32(ddlDepartmentID.SelectedValue);
                courses.CreatedDate  = Convert.ToDateTime(txtCreatedDate.Text);
                courses.CreatedBy    = txtCreatedBy.Text;
                courses.UpdatedDate  = Convert.ToDateTime(txtUpdatedDate.Text);
                courses.UpdatedBy    = txtUpdatedBy.Text;

                CoursesService coursesService = new CoursesService();
                coursesService.AddCourses(courses);
            }
            if (coursesID != null)
            {
                Contoso.Models.Courses courses = new Models.Courses();
                courses.ID           = Convert.ToInt32(coursesID);
                courses.Title        = txtTitle.Text;
                courses.Credits      = Convert.ToInt32(txtCredits.Text);
                courses.DepartmentID = Convert.ToInt32(ddlDepartmentID.SelectedValue);
                courses.CreatedDate  = Convert.ToDateTime(txtCreatedDate.Text);
                courses.CreatedBy    = txtCreatedBy.Text;
                courses.UpdatedDate  = Convert.ToDateTime(txtUpdatedDate.Text);
                courses.UpdatedBy    = txtUpdatedBy.Text;

                CoursesService coursesService = new CoursesService();
                coursesService.UpdateCourses(courses);
            }
        }