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基于对象职责明确原则优化程序

学习了如何编写通用数据访问类SQLHelper,在此基础上还可以继续优化程序,基于对象职责明确原则,将程序封装成学生数据信息访问类、班级信息访问类、成绩信息访问类等。

 1     /// <summary>
 2     /// 学员信息数据访问类
 3     /// </summary>
 4     class StudentService
 5     {
 6         public int AddStudent(string studentName, string gender, DateTime birthday,
 7             string stuIdNo, int age, string phoneNumber, string stuAddress, int classId)
 8         {
 9             string sql = "insert into Students(StudentName,Gender,Birthday,studentIdNo,Age,PhoneNumber,studentAddress, classId)";
10             sql += "values(‘{0}‘,‘{1}‘,‘{2}‘,{3},{4},‘{5}‘,‘{6}‘,{7})";
11             sql = string.Format(sql, studentName, gender, birthday, stuIdNo, age, phoneNumber, stuAddress, classId);
12             return SQLHelper.Update(sql);
13         }
14 }

 

 1         static void Main(string[] args)
 2         {
 3             //获取用户输入
 4             Console.WriteLine("请输入学员姓名:");
 5             string stuName = Console.ReadLine();
 6             Console.WriteLine("请输入学员性别:");
 7             string gender = Console.ReadLine();
 8             Console.WriteLine("请输入学员出生日期:");
 9             DateTime birthday = Convert.ToDateTime(Console.ReadLine());
10             Console.WriteLine("请输入学员身份证号:");
11             string stuIdNo = Console.ReadLine();
12             Console.WriteLine("请输入学员年龄:");
13             int age = Convert.ToInt16(Console.ReadLine());
14             Console.WriteLine("请输入学员电话:");
15             string phoneNumber = Console.ReadLine();
16             Console.WriteLine("请输入学员身份地址:");
17             string stuAddress = Console.ReadLine();
18             Console.WriteLine("请输入学员班级编号:");
19             int classId = Convert.ToInt16(Console.ReadLine());
20 
21             //调用数据访问方法
22             StudentService objstuService = new StudentService();
23             int result = objstuService.AddStudent(stuName, gender, birthday, stuIdNo, age, phoneNumber, stuAddress, classId);
24             //展示结果
25             Console.WriteLine(result);
26             Console.ReadLine();
27         }

但是以上代码存在缺点:方法参数多

1.定义和使用不方便,容易把参数写错

2.当对象是属性变化时,方法的参数必须改变

问题解学办法:使用实体类作为方法参数,稳定对外接口

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Linq;
 4 using System.Text;
 5 using System.Threading.Tasks;
 6 
 7 namespace ASP.NETDemo
 8 {
 9     /// <summary>
10     /// 学生实体类
11     /// </summary>
12     class Student
13     {
14         public int StudentId { get; set; }
15         public string StudentName { get; set; }
16         public string Gender { get; set; }
17         public DateTime Birthday { get; set; }
18         public decimal StudentIdNo { get; set; }
19         public int Age { get; set; }
20         public string PhoneNumber { get; set; }
21         public string StudentAddress { get; set; }
22         public int ClassId { get; set; }
23     }
24 }

优化后

1        public int AddStudent(Student objStudent)
2         {
3             string sql = "insert into Students(StudentName,Gender,Birthday,studentIdNo,Age,PhoneNumber,studentAddress, classId)";
4             sql += "values(‘{0}‘,‘{1}‘,‘{2}‘,{3},{4},‘{5}‘,‘{6}‘,{7})";
5             sql = string.Format(sql,objStudent.StudentName,objStudent.Gender,objStudent.Birthday,objStudent.StudentIdNo,objStudent.Age,objStudent.PhoneNumber,objStudent.StudentAddress, objStudent.ClassId);
6             return SQLHelper.Update(sql);
7         }
 1        static void Main(string[] args)
 2         {
 3             //创建学员对象
 4             Student objStu = new Student();
 5             
 6             //获取用户输入,封装学员对象
 7             Console.WriteLine("请输入学员姓名:");
 8             objStu.StudentName = Console.ReadLine();
 9             Console.WriteLine("请输入学员性别:");
10             objStu.Gender = Console.ReadLine();
11             Console.WriteLine("请输入学员出生日期:");
12             objStu.Birthday = Convert.ToDateTime(Console.ReadLine());
13             Console.WriteLine("请输入学员身份证号:");
14             objStu.StudentIdNo =Convert.ToDecimal( Console.ReadLine());
15             Console.WriteLine("请输入学员年龄:");
16             objStu.Age = Convert.ToInt16(Console.ReadLine());
17             Console.WriteLine("请输入学员电话:");
18             objStu.PhoneNumber = Console.ReadLine();
19             Console.WriteLine("请输入学员身份地址:");
20             objStu.StudentAddress = Console.ReadLine();
21             Console.WriteLine("请输入学员班级编号:");
22             objStu.ClassId = Convert.ToInt16(Console.ReadLine());
23 
24             //调用数据访问方法
25             StudentService objstuService = new StudentService();
26             int result = objstuService.AddStudent(objStu);
27             //展示结果
28             Console.WriteLine(result);
29             Console.ReadLine();
30         }

 

基于对象职责明确原则优化程序