private void TeacherAdd_Click(object sender, EventArgs e)//添加、修改按钮
        {
            Teacher teacher = new Teacher()
            {
                tno    = Tno.Text,
                tname  = Tname.Text,
                sex    = Sex.Text,
                title  = Title.Text,
                deptno = DeptnoT.Text,
                tid    = Tid.Text
            };
            TeacherBLL teacherBLL = new TeacherBLL();

            #region 添加
            if (TeacherAdd.Text.Equals("添加"))
            {
                if (teacherBLL.Add(teacher))
                {
                    MessageBox.Show("添加成功");

                    LoadTeacherList();
                }
                else
                {
                    MessageBox.Show("添加失败");
                }
            }
            #endregion
            #region 修改
            else
            {
                if (teacherBLL.Edit(teacher))
                {
                    MessageBox.Show("修改成功");
                    LoadTeacherList();
                    Tno.ReadOnly    = false;
                    TeacherAdd.Text = "添加";
                }
                else
                {
                    MessageBox.Show("修改失败");
                }
            }
            #endregion
            Tno.Text     = "";
            Tname.Text   = "";
            Sex.Text     = "";
            Title.Text   = "";
            DeptnoT.Text = "";
            Tid.Text     = "";
        }