protected void EnrollCoursesButton_Click(object sender, EventArgs e)
        {
            EnrollCourse _EnrollCourse = new EnrollCourse();

            _EnrollCourse.DepartmentId = Convert.ToInt32(DepartmentDropDownList.SelectedValue);
            _EnrollCourse.DeptCode     = DepartmentDropDownList.SelectedItem.ToString();
            _EnrollCourse.StudentRegNo = StudentRegNoDropDownList.SelectedItem.ToString();
            _EnrollCourse.EnrollDate   = DateTime.Now.ToShortDateString();
            _EnrollCourse.CourseCode   = CoursesDropDownList.SelectedValue.ToString();
            _EnrollCourse.CourseName   = CoursesDropDownList.SelectedItem.ToString();
            _EnrollCourse.StudentId    = Convert.ToInt32(StudentRegNoDropDownList.SelectedValue);
            decimal AlreadyCourseAssign = _EnrollCourseManager.AlreadyCourseAssign(_EnrollCourse);

            if (AlreadyCourseAssign >= 1)
            {
                ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('This Code Already Enroll');", true);
            }
            else
            {
                int success = _EnrollCourseManager.EnrollCourse(_EnrollCourse);
                if (success > 0)
                {
                    ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('Succssefully Enroll Course');", true);
                }
                else
                {
                    ClientScript.RegisterStartupScript(this.GetType(), "alert", "alert('Failed Enroll ');", true);
                }
            }
        }