/// <summary>
        /// 根据班级查询学生列表
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void BtnQuery_Click(object sender, EventArgs e)
        {
            if (this.cboClass.SelectedIndex == -1)
            {
                MessageBox.Show("请选择班级", "提示信息");
                return;
            }

            var          studentClassId = Convert.ToInt32(this.cboClass.SelectedValue);
            StudentClass studentClass   = new StudentClass()
            {
                ClassId = studentClassId
            };

            var studentsList = studentClassService.QueryStudentsByClassId(studentClass);

            if (studentsList.Count == 0)
            {
                this.dgvStudentList.DataSource = null;
                MessageBox.Show("查询结果为空!", "提示信息");
                return;
            }
            this.dgvStudentList.DataSource = null;
            this.dgvStudentList.DataSource = studentsList;
            this.dgvStudentList.ClearSelection();
        }