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  • part01.01 C#基础语法与逻辑控制（四）（6. C# 类）

    C# 类

    类的声明

     1  /// <summary>
 2     /// 学校教学班
 3     /// </summary>
 4     public class SchoolClass
 5     {
 6         //public Guid ID = Guid.NewGuid();    // 属性的直接处理方式
 7         public Guid ID { get; set; }    //  教学班标识符，唯一标识符
 8         public string Name { get; set; }    //  教学班名称
 9         public string Description { get; set; }     //  教学班简要说明
10         public string SortCode { get; set; }    //  业务编码
11         public DateTime CreateTime { get; set; }    //  创建日期
12         public GradeEnum Grade { get; set; }    //  归属年级
13         public bool IsActive { get; set; }      //  是否为在校教学班（否表示已不是）
14 
15         public SchoolClass()
16         {
17             this.ID = Guid.NewGuid();
18         }
19     }
20 
21  /// <summary>
22     /// 学生
23     /// </summary>
24     public class Student
25     {
26         public Guid ID { get; set; }                   // 唯一标识符
27         public string Name { get; set; }               // 学生姓名
28         public string Description { get; set; }        // 简要说明
29         public string SortCode { get; set; }           // 学号
30         public bool Sex { get; set; }                  // 性别
31         public DateTime BirthDay { get; set; }         // 出生日期
32         public string Origin { get; set; }             // 籍贯
33 
34         public SchoolClass SchoolClass { get; set; }   // 归属的教学班
35 
36  /// <summary>
37         /// 构造函数，创建实例并为标识符赋值
38         /// </summary>
39         public Student()
40         {
41             this.ID = Guid.NewGuid();          
42         }
43 }
44 
45  /// <summary>
46     /// 年级
47     /// </summary>
48     public enum GradeEnum
49     {
50         初一, 初二, 初三,
51         高一, 高二, 高三
52     }
    View Code

    对象：类的实例化

     1 /// <summary>
 2     /// 演示类和对象构建的一般方法
 3     /// </summary>
 4     class Program
 5     {
 6         static void Main(string[] args)
 7         {
 8 
 9             #region 传统的创建业务实体对象的写法
10             Student student01 = new Student();
11 
12             student01.Name = "张文华";
13             student01.Description = "张文华的简要说明";
14             student01.SortCode = "20160901H001";
15             student01.Sex = true;
16             student01.BirthDay = DateTime.Parse("1990-08-18");
17             student01.Origin = "广西桂林";
18             #endregion
19 
20             #region 现代的创建业务实体对象的写法
21             var student02 = new Student()
22             {
23                 Name = "张文华",
24                 Description = "张文华的简要说明",
25                 SortCode = "20160901H001",
26                 Sex = true,
27                 BirthDay = DateTime.Parse("1990-08-18"),
28                 Origin = "广西桂林"
29             }; 
30             #endregion
31        }
32 }
    View Code

    类属性的修饰符

    private 和 readonly 的简要说明

    属性的直接处理方式（注：partial 是定义局部类的关键字，下面会做详细的解释）

    字段的属性的概念

    （字段）

    （属性）

     构造函数重构

     1  /// <summary>
 2         /// 构造函数，创建实例并为标识符赋值
 3         /// </summary>
 4         public Student()
 5         {
 6             this.ID = Guid.NewGuid();
 7             #region 在构造函数中可以为私有变量和只读变量赋值
 8             //this._PrivateInformation01 = "隐私性质的信息01";
 9             //this._PrivateInformation02 = "隐私性质的信息01";
10             //this._ReadOnlyInformation = "只读性质的信息";
11             #endregion
12         }
13     
14         /// <summary>
15         /// 重载构造函数，直接为属性赋值
16         /// </summary>
17         /// <param name="name"></param>
18         /// <param name="description"></param>
19         /// <param name="sortcode"></param>
20         /// <param name="sex"></param>
21         /// <param name="birthday"></param>
22         /// <param name="origin"></param>
23         public Student(string name,string description, string sortcode, bool sex, DateTime birthday, string origin)
24         {
25             this.ID = Guid.NewGuid();
26             this.Name = name;
27             this.Description = description;
28             this.SortCode = sortcode;
29             this.Sex = sex;
30             this.BirthDay = birthday;
31             this.Origin = origin;
32         }
    View Code

    静态类和和静态方法

    静态类基本和非静态类相同，但存在一个差异：静态类无法实例化，就是无法使用 new 关键字创建类类型的变量，由于不存在任何实例变量，因此可以使用类名本身访问静态类成员

    具体代码如下：

      1  /// <summary>
  2     /// 对学生数据进行持久化处理的常规方法
  3     /// </summary>
  4     public static class DataStore
  5     {
  6         /// <summary>
  7         /// 保存 student 对象数据
  8         /// </summary>
  9         /// <param name="employee"></param>
 10         public static void Save(Student student)
 11         {
 12             //  使用 student 对象的 ID+dat 作为数据存储的文件名，保存对象数据
 13             var stream = new FileStream(student.ID + "dat", FileMode.Create);
 14             //  通过 StreamWriter 对象将传入的 employee 数据存储到前面创建的文件中
 15             using (var writer = new StreamWriter(stream))
 16             {
 17                 writer.WriteLine(student.ID);
 18                 writer.WriteLine(student.Name);
 19                 writer.WriteLine(student.Description);
 20                 writer.WriteLine(student.SortCode);
 21                 writer.WriteLine(student.Sex);
 22                 writer.WriteLine(student.BirthDay);
 23                 writer.WriteLine(student.Origin);
 24                 if (student.SchoolClass != null)
 25                     writer.WriteLine(student.SchoolClass.Name);
 26 
 27                 writer.Close();     //  关闭文件流
 28             }
 29         }
 30 
 31         /// <summary>
 32         /// 从存储数据的文件中读取数据并转换为相应的 Student 对象
 33         /// </summary>
 34         /// <param name="id">对象的 id </param>
 35         /// <returns></returns>
 36         public static Student Get(Guid id)
 37         {
 38             var student = new Student();
 39             var stream = new FileStream(id.ToString() + "dat", FileMode.Open);
 40             //  通过 StreamReader 读取文件数据，赋值到对象相关属性
 41             using(var reader=new StreamReader(stream))
 42             {
 43                 student.ID = Guid.Parse(reader.ReadLine());
 44                 student.Name = reader.ReadLine();
 45                 student.Description = reader.ReadLine();
 46                 student.SortCode = reader.ReadLine();
 47                 student.Sex = Boolean.Parse(reader.ReadLine());
 48                 student.BirthDay = DateTime.Parse(reader.ReadLine());
 49                 student.Origin = reader.ReadLine();
 50                 reader.Close();
 51                 return student;
 52                
 53               
 54             }
 55         }
 56 
 57         /// <summary>
 58         /// 初始化一批教学班数据，供程序使用
 59         /// </summary>
 60         /// <returns></returns>
 61         public static List<SchoolClass> CreateSchoolClassCollection()
 62         {
 63             var schoolClassCollection = new List<SchoolClass>();
 64 
 65             var sc01 = new SchoolClass()
 66             {
 67                 Name = "高一1班",
 68                 Description = "关于高一1班的说明",
 69                 SortCode = "20170901H",
 70                 CreateDate = DateTime.Parse("2017-09-01"),
 71                 GradeEnum = GradeEnum.高一,
 72                 IsActive = true
 73             };
 74             schoolClassCollection.Add(sc01);
 75 
 76             var sc02 = new SchoolClass()
 77             {
 78                 Name = "高一2班",
 79                 Description = "关于高一2班的说明",
 80                 SortCode = "20170902H",
 81                 CreateDate = DateTime.Parse("2017-09-01"),
 82                 GradeEnum = GradeEnum.高一,
 83                 IsActive = true
 84             };
 85             schoolClassCollection.Add(sc02);
 86 
 87             var sc03 = new SchoolClass()
 88             {
 89                 Name = "高一3班",
 90                 Description = "关于高一3班的说明",
 91                 SortCode = "20170903H",
 92                 CreateDate = DateTime.Parse("2017-09-01"),
 93                 GradeEnum = GradeEnum.高一,
 94                 IsActive = true
 95             };
 96             schoolClassCollection.Add(sc03);
 97 
 98             var sc04 = new SchoolClass()
 99             {
100                 Name = "高二1班",
101                 Description = "关于高二1班的说明",
102                 SortCode = "20160901H",
103                 CreateDate = DateTime.Parse("2016-09-01"),
104                 GradeEnum = GradeEnum.高二,
105                 IsActive = true
106             };
107             schoolClassCollection.Add(sc04);
108 
109             var sc05 = new SchoolClass()
110             {
111                 Name = "高二2班",
112                 Description = "关于高一1班的说明",
113                 SortCode = "20160902H",
114                 CreateDate = DateTime.Parse("2016-09-01"),
115                 GradeEnum = GradeEnum.高二,
116                 IsActive = true
117             };
118             schoolClassCollection.Add(sc05);
119 
120             var sc06 = new SchoolClass()
121             {
122                 Name = "高二3班",
123                 Description = "关于高二3班的说明",
124                 SortCode = "20170903H",
125                 CreateDate = DateTime.Parse("2016-09-01"),
126                 GradeEnum = GradeEnum.高二,
127                 IsActive = true
128             };
129             schoolClassCollection.Add(sc06);
130 
131             return schoolClassCollection;
132         }
133     }
    View Code

     扩展方法（针对 Student 类的扩展（动态编程））

     1  /// <summary>
 2     /// 针对 Student 类的扩展（动态编程）
 3     /// </summary>
 4     public static class StudentExtension
 5     {
 6         /// <summary>
 7         /// 打印学生数据到控制台
 8         /// </summary>
 9         /// <param name="student">学生对象</param>
10         public static void Print(this Student student)
11         {
12             Console.WriteLine(student.ToString());
13         }
14     }
    View Code

    特殊的类（内嵌类、局部类）

    内嵌类

     

    相关代码

     1   /// <summary>
 2     /// 学生
 3     /// </summary>
 4     public class Student
 5     {
 6         public Guid ID { get; set; }                   // 唯一标识符
 7         public string Name { get; set; }               // 学生姓名
 8         public string Description { get; set; }        // 简要说明
 9         public string SortCode { get; set; }           // 学号
10         public bool Sex { get; set; }                  // 性别
11         public DateTime BirthDay { get; set; }         // 出生日期
12         public string Origin { get; set; }             // 籍贯
13 
14         public SchoolClass SchoolClass { get; set; }   // 归属的教学班
15 
16         //private string _PrivateInformation01;          // 私有变量01
17         //private string _PrivateInformation02 { get; }  // 私有变量02，并且只能读取
18         //readonly string _ReadOnlyInformation;          // 只读性质的信息
19 
20         /// <summary>
21         /// 构造函数，创建实例并为标识符赋值
22         /// </summary>
23         public Student()
24         {
25             this.ID = Guid.NewGuid();
26             #region 在构造函数中可以为私有变量和只读变量赋值
27             //this._PrivateInformation01 = "隐私性质的信息01";
28             //this._PrivateInformation02 = "隐私性质的信息01";
29             //this._ReadOnlyInformation = "只读性质的信息";
30             #endregion
31         }
32     
33         /// <summary>
34         /// 重载构造函数，直接为属性赋值
35         /// </summary>
36         /// <param name="name"></param>
37         /// <param name="description"></param>
38         /// <param name="sortcode"></param>
39         /// <param name="sex"></param>
40         /// <param name="birthday"></param>
41         /// <param name="origin"></param>
42         public Student(string name,string description, string sortcode, bool sex, DateTime birthday, string origin)
43         {
44             this.ID = Guid.NewGuid();
45             this.Name = name;
46             this.Description = description;
47             this.SortCode = sortcode;
48             this.Sex = sex;
49             this.BirthDay = birthday;
50             this.Origin = origin;
51         }
52 
53         /// <summary>
54         /// 将对象数据格式化处理，可以用于前端显示
55         /// </summary>
56         /// <returns></returns>
57         public override string ToString()
58         {
59             //this._PrivateInformation01 = "更新后的隐私信息";   
60             //this._PrivateInformation02 = "更新后的隐私信息";   // 不能在方法中更新只读私有变量
61             //this._ReadOnlyInformation = "更新后的只读信息";    // 不能在方法中更新只读变量
62 
63             var sexString = "男";
64             if (!this.Sex)
65                 sexString = "女";
66             var birthday = this.BirthDay.ToLongDateString();
67 
68             var result = string.Format("学生数据： 	{0} 	{1} 	{2} 	{3} 	{4} 	{5}", this.ID, this.Name, this.SortCode, sexString, birthday, this.Origin);
69             return result;
70         }
71 
72         /// <summary>
73         /// 内嵌类：联系方式
74         /// </summary>
75         public class Contact
76         {
77             public string Mobile { get; set; }
78             public string EMail { get; set; }
79             public string QQ { get; set; }
80         }
81     }
    View Code

    局部类

    相关代码

     1  /// <summary>
 2     /// 教师
 3     /// </summary>
 4     public partial class Teacher
 5     {
 6         public Guid ID { get; set; }              // 唯一标识符
 7         public string Name { get; set; }          // 教师姓名
 8         public string Description { get; set; }   // 简要说明
 9         public string SortCode { get; set; }      // 工号
10         public bool Sexe { get; set; }            // 性别
11         public DateTime BirthDay { get; set; }    // 出生日期
12         public string Origin { get; set; }        // 籍贯
13 
14         public Teacher()
15         {
16             this.ID = Guid.NewGuid();
17         }
18     }
19     /// <summary>
20     /// 作为 Teacher 局部类，补充类 Teacher 的属性或方法
21     /// </summary>   
22     public partial class Teacher
23     {
24         public DateTime JoiningDate { get; set; }   //  入职时间
25     }
    View Code
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  • 原文地址：https://www.cnblogs.com/huangzewei/p/7278459.html
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