private void Del_Click(object sender, EventArgs e) { if (txtCourseNum.Text == "") { MessageBox.Show("课程号不能为空!\n 请重新输入!"); } else { CourseBLL objCourseBLL = new CourseBLL(); CourseModel objCourseModel = new CourseModel(); objCourseModel.CourseNum = txtCourseNum.Text; if (objCourseBLL.DelCourse(objCourseModel) == true) { MessageBox.Show("成功删除!!"); } else { MessageBox.Show("删除失败!"); } ShowTable(); } }