c#學習筆記-深度複製 與淺度複製

 關於值類型和引用類型：

淺度複製(shallow copy)只複製值類型(char,int )的值，而對於引用類型不會複製，淺度複製可以通過派生於System.Object的MemberwiseClone()方法來完成，這是一個受保護的方法。因為他並沒有考慮引用類型成員，因此新對象的引用成員就會指向源對象中的相同成員引用的對象

如果要創建成員的新實例(複製值，而不是複製引用)就需要用到深度複製(deep copy)

深度複製需要實現一個ICloneable介面，如果使用這個介面需要實現它包含的Clone()方法，這個方法返回一個System.Object的值，

下麵看下淺度複製：

 1 public class Company
 2     {
 3         public string value { get; set; }
 4     }
 5 
 6     public class Phone
 7     {
 8        public string color { get; set; }
 9 
10        public  Company company = new Company();
11 
12         public Phone (string newCompany)
13         {
14             company.value = newCompany;
15         }
16 
17         public object getCopy()
18         {
19             return MemberwiseClone();
20         }
21     }

 1  static void Main(string[] args)
 2         {
 3             Phone phone = new Phone("xiaomi");
 4             phone.color = "red";
 5             Phone phone1 = (Phone)phone.getCopy();            
 6             Console.WriteLine($"phone company:{phone.company.value} color: {phone.color}");
 7             Console.WriteLine($"phone1 company:{phone1.company.value} color: {phone1.color}");
 8 
 9             Console.WriteLine("淺度複製修改新對象的值");
10 
11             phone1.company.value = "huawei";
12             phone1.color = "green";
13             Console.WriteLine($"phone company:{phone.company.value} color: {phone.color}");
14             Console.WriteLine($"phone1 company:{phone1.company.value} color: {phone1.color}");
15             Console.ReadKey();
16 
17         }

實驗現象：

淺度複製在後引用類型修改後，原對象也跟著發生了改變

修改這個問題，可以使用深度複製

 1 public class Company
 2     {
 3         public string value { get; set; }
 4     }
 5 
 6     public class Phone:ICloneable
 7     {
 8        public string color { get; set; }
 9 
10        public  Company company = new Company();
11 
12         public Phone (string newCompany)
13         {
14             company.value = newCompany;
15         }
16 
17         public object getCopy()
18         {
19             return MemberwiseClone();
20         }
21 
22         public object Clone()
23         {
24             Phone newPhone = new Phone(company.value);
25             return newPhone;
26             //newPhone.company.value = this.company.value;
27 
28         }
29     }

 1 static void Main(string[] args)
 2         {
 3             Phone phone = new Phone("xiaomi");
 4             phone.color = "red";
 5             Phone phone1 = (Phone)phone.Clone();            
 6             Console.WriteLine($"phone company:{phone.company.value} color: {phone.color}");
 7             Console.WriteLine($"phone1 company:{phone1.company.value} color: {phone1.color}");
 8 
 9             Console.WriteLine("淺度複製修改新對象的值");
10 
11             phone1.company.value = "huawei";
12             phone1.color = "green";
13             Console.WriteLine($"phone company:{phone.company.value} color: {phone.color}");
14             Console.WriteLine($"phone1 company:{phone1.company.value} color: {phone1.color}");
15             Console.ReadKey();
16 
17         }

實驗現象