一，添加查询对象的实体类，数据访问类，业务逻辑类 实体类数据访问类 namespace DAL {public class StudentService{/// <summary>/// 根据班级名称查询学员信息/// </summary>/// <param name="className">班级名称</param>/// <returns>学员信息列表</returns>public List<Student> GetStudentByClass(string className){string sql = "select StudentId, StudentName, Gender, Birthday, StudentIdNo, CardNo, PhoneNumber, Stu...