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[ASP.net教程][C#进阶系列]专题一:深入解析深拷贝和浅拷贝


一、前言

  这个星期参加了一个面试,面试中问到深浅拷贝的区别,然后我就简单了讲述了它们的之间的区别,然后面试官又继续问,如何实现一个深拷贝呢?当时只回答回答了一种方式,就是使用反射,然后面试官提示还可以通过反序列化和表达树的方式。然后又继续问,如果用反射来实现深拷贝的话,如何解决互相引用对象的问题呢? 当时我给出的答案是说那就不用反射去实现呗,用反序列化实现呗,或者直接避免使两个对象互相引用呗。然后面试官说,如果一定用反射来写,你是怎么去解决这个问题呢?这时候我就愣住了。

  这样也就有了这篇文章。今天就来深入解析下深浅拷贝的问题。

二、深拷贝 Vs 浅拷贝

  首先,讲到深浅拷贝,自然就有一个问题来了?什么是深拷贝,什么又是浅拷贝呢?下面就具体介绍下它们的定义。

  深拷贝:指的是拷贝一个对象时,不仅仅把对象的引用进行复制,还把该对象引用的值也一起拷贝。这样进行深拷贝后的拷贝对象就和源对象互相独立,其中任何一个对象的改动都不会对另外一个对象造成影响。举个例子,一个人叫张三,然后使用克隆技术以张三来克隆另外一个人叫李四,这样张三和李四就是相互独立的,不管张三缺胳膊还是李四少腿了都不会影响另外一个人。在.NET领域,值对象就是典型的例子,如int, Double以及结构体和枚举等。具体例子如下所示:

int source = 123;// 值类型赋值内部执行深拷贝int copy = source;// 对拷贝对象进行赋值不会改变源对象的值copy = 234;// 同样对源对象赋值也不会改变拷贝对象的值source = 345;

  浅拷贝:指的是拷贝一个对象时,仅仅拷贝对象的引用进行拷贝,但是拷贝对象和源对象还是引用同一份实体。此时,其中一个对象的改变都会影响到另一个对象。例如,一个人一开始叫张三,后来改名字为张老三了,可是他们还是同一个人,不管张三缺胳膊还是张老三少腿,都反应在同一个人身上。在.NET中引用类型就是一个例子。如类类型。具体例子如下所示:

public class Person  {    public string Name { get; set; }  }  class Program  {    static void Main(string[] args)    {      Person sourceP = new Person() { Name = "张三" };      Person copyP = sourceP; // 浅拷贝      copyP.Name = "张老三"; // 拷贝对象改变Name值      // 结果都是"张老三",因为实现的是浅拷贝,一个对象的改变都会影响到另一个对象      Console.WriteLine("Person.Name: [SourceP: {0}] [CopyP:{1}]", sourceP.Name, copyP.Name);      Console.Read();    }  }

三、深浅拷贝的几种实现方式

   上面已经明白了深浅拷贝的定义,至于他们之间的区别也在定义中也有所体现。介绍完了它们的定义和区别之后,自然也就有了如何去实现它们呢?

  对于,浅拷贝的实现方式很简单,.NET自身也提供了实现。我们知道,所有对象的父对象都是System.Object对象,这个父对象中有一个MemberwiseClone方法,该方法就可以用来实现浅拷贝,下面具体看看浅拷贝的实现方式,具体演示代码如下所示:

// 继承ICloneable接口,重新其Clone方法  class ShallowCopyDemoClass : ICloneable  {    public int intValue = 1;    public string strValue = "1";    public PersonEnum pEnum = PersonEnum.EnumA;    public PersonStruct pStruct = new PersonStruct() { StructValue = 1};    public Person pClass = new Person("1");    public int[] pIntArray = new int[] { 1 };    public string[] pStringArray = new string[] { "1" };    #region ICloneable成员    public object Clone()    {      return this.MemberwiseClone();    }    #endregion   }  class Person  {    public string Name;    public Person(string name)    {      Name = name;    }  }  public enum PersonEnum  {    EnumA = 0,    EnumB = 1  }  public struct PersonStruct  {    public int StructValue;  }

  上面类中重写了IConeable接口的Clone方法,其实现直接调用了Object的MemberwiseClone方法来完成浅拷贝,如果想实现深拷贝,也可以在Clone方法中实现深拷贝的逻辑。接下来就是对上面定义的类进行浅拷贝测试了,看看是否是实现的浅拷贝,具体演示代码如下所示:

class Program  {    static void Main(string[] args)    {      ShallowCopyDemo();      // List浅拷贝的演示      ListShallowCopyDemo();    }    public static void ListShallowCopyDemo()    {      List<PersonA> personList = new List<PersonA>()       {        new PersonA() { Name="PersonA", Age= 10, ClassA= new A() { TestProperty = "AProperty"} },        new PersonA() { Name="PersonA2", Age= 20, ClassA= new A() { TestProperty = "AProperty2"} }      };       // 下面2种方式实现的都是浅拷贝      List<PersonA> personsCopy = new List<PersonA>(personList);      PersonA[] personCopy2 = new PersonA[2];      personList.CopyTo(personCopy2);
       // 由于实现的是浅拷贝,所以改变一个对象的值,其他2个对象的值都会发生改变,因为它们都是使用的同一份实体,即它们指向内存中同一个地址  personsCopy.First().ClassA.TestProperty = "AProperty3"; WriteLog(string.Format("personCopy2.First().ClassA.TestProperty is {0}", personCopy2.First().ClassA.TestProperty)); WriteLog(string.Format("personList.First().ClassA.TestProperty is {0}", personList.First().ClassA.TestProperty)); WriteLog(string.Format("personsCopy.First().ClassA.TestProperty is {0}", personsCopy.First().ClassA.TestProperty));
       Console.Read();  } public static void ShallowCopyDemo() { ShallowCopyDemoClass DemoA = new ShallowCopyDemoClass(); ShallowCopyDemoClass DemoB = DemoA.Clone() as ShallowCopyDemoClass ; DemoB.intValue = 2; WriteLog(string.Format(" int->[A:{0}] [B:{1}]", DemoA.intValue, DemoB.intValue)); DemoB.strValue = "2"; WriteLog(string.Format(" string->[A:{0}] [B:{1}]", DemoA.strValue, DemoB.strValue)); DemoB.pEnum = PersonEnum.EnumB; WriteLog(string.Format(" Enum->[A: {0}] [B:{1}]", DemoA.pEnum, DemoB.pEnum)); DemoB.pStruct.StructValue = 2; WriteLog(string.Format(" struct->[A: {0}] [B: {1}]", DemoA.pStruct.StructValue, DemoB.pStruct.StructValue)); DemoB.pIntArray[0] = 2; WriteLog(string.Format(" intArray->[A:{0}] [B:{1}]", DemoA.pIntArray[0], DemoB.pIntArray[0])); DemoB.pStringArray[0] = "2"; WriteLog(string.Format("stringArray->[A:{0}] [B:{1}]", DemoA.pStringArray[0], DemoB.pStringArray[0])); DemoB.pClass.Name = "2"; WriteLog(string.Format(" Class->[A:{0}] [B:{1}]", DemoA.pClass.Name, DemoB.pClass.Name));
       Console.WriteLine();
      }
private static void WriteLog(string msg) { Console.WriteLine(msg); }   } }

  上面代码的运行结果如下图所示:

  从上面运行结果可以看出,.NET中值类型默认是深拷贝的,而对于引用类型,默认实现的是浅拷贝。所以对于类中引用类型的属性改变时,其另一个对象也会发生改变。

  上面已经介绍了浅拷贝的实现方式,那深拷贝要如何实现呢?在前言部分已经介绍了,实现深拷贝的方式有:反射、反序列化和表达式树。在这里,我只介绍反射和反序列化的方式,对于表达式树的方式在网上也没有找到,当时面试官说是可以的,如果大家找到了表达式树的实现方式,麻烦还请留言告知下。下面我们首先来看看反射的实现方式吧:

// 利用反射实现深拷贝    public static T DeepCopyWithReflection<T>(T obj)    {      Type type = obj.GetType();      // 如果是字符串或值类型则直接返回      if (obj is string || type.IsValueType) return obj;      if (type.IsArray)      {        Type elementType = Type.GetType(type.FullName.Replace("[]", string.Empty));        var array = obj as Array;        Array copied = Array.CreateInstance(elementType, array.Length);        for (int i = 0; i < array.Length; i++)        {          copied.SetValue(DeepCopyWithReflection(array.GetValue(i)), i);        }        return (T)Convert.ChangeType(copied, obj.GetType());      }      object retval = Activator.CreateInstance(obj.GetType());            PropertyInfo[] properties = obj.GetType().GetProperties(        BindingFlags.Public | BindingFlags.NonPublic        | BindingFlags.Instance | BindingFlags.Static);      foreach (var property in properties)      {        var propertyValue = property.GetValue(obj, null);        if (propertyValue == null)          continue;        property.SetValue(retval, DeepCopyWithReflection(propertyValue), null);      }      return (T)retval;    }

  反序列化的实现方式,反序列化的方式也可以细分为3种,具体的实现如下所示:

 // 利用    public static T DeepCopyWith(T obj)    {      object retval;      using (MemoryStream ms = new MemoryStream())      {        = new typeof(T));        0, SeekOrigin.Begin);        retval = return (T)retval;    }    // 利用二进制序列化和反序列实现    public static T DeepCopyWithBinarySerialize<T>(T obj)    {      object retval;      using (MemoryStream ms = new MemoryStream())      {        BinaryFormatter bf = new BinaryFormatter();        // 序列化成流        bf.Serialize(ms, obj);        ms.Seek(0, SeekOrigin.Begin);        // 反序列化成对象        retval = bf.Deserialize(ms);        ms.Close();      }      return (T)retval;    }    // 利用DataContractSerializer序列化和反序列化实现    public static T DeepCopy<T>(T obj)    {      object retval;      using (MemoryStream ms = new MemoryStream())      {        DataContractSerializer ser = new DataContractSerializer(typeof(T));        ser.WriteObject(ms, obj);        ms.Seek(0, SeekOrigin.Begin);        retval = ser.ReadObject(ms);        ms.Close();      }      return (T)retval;    }        // 表达式树实现    // ....

四、使用反射进行深拷贝如何解决相互引用的问题

  上面反射的实现方式,对于相互引用的对象会出现StackOverflower的错误,由于对象的相互引用,会导致方法循环调用。下面就是一个相互引用对象的例子:

[Serializable]  public class DeepCopyDemoClass  {    public string Name {get;set;}    public int[] pIntArray { get; set; }    public Address Address { get; set; }    public DemoEnum DemoEnum { get; set; }    // DeepCopyDemoClass中引用了TestB对象,TestB类又引用了DeepCopyDemoClass对象,从而造成了相互引用    public TestB TestB {get;set;}    public override string ToString()    {      return "DeepCopyDemoClass";    }  }  [Serializable]  public class TestB  {    public string Property1 { get; set; }    public DeepCopyDemoClass DeepCopyClass { get; set; }    public override string ToString()    {      return "TestB Class";    }  }  [Serializable]  public struct Address  {    public string City { get; set; }  }  public enum DemoEnum  {    EnumA = 0,    EnumB = 1  }

  在面试过程中,针对这个问题的解决方式我回答的是不知道,回来之后思考了之后,也就有了点思路。首先想到的是:能不能用一个字典来记录每个对象被反射的次数,仔细想想可行,于是开始实现,初步修复后的反射实现如下所示:

 public class DeepCopyHelper  {    // 用一个字典来存放每个对象的反射次数来避免反射代码的循环递归    static Dictionary<Type, int> typereflectionCountDic = new Dictionary<Type, int>(); public static T DeepCopyWithReflection_Second<T>(T obj)    {      Type type = obj.GetType();      // 如果是字符串或值类型则直接返回      if (obj is string || type.IsValueType) return obj;      if (type.IsArray)      {        Type elementType = Type.GetType(type.FullName.Replace("[]", string.Empty));        var array = obj as Array;        Array copied = Array.CreateInstance(elementType, array.Length);        for (int i = 0; i < array.Length; i++)        {          copied.SetValue(DeepCopyWithReflection_Second(array.GetValue(i)), i);        }        return (T)Convert.ChangeType(copied, obj.GetType());      }      // 对于类类型开始记录对象反射的次数      int reflectionCount = Add(typereflectionCountDic, obj.GetType());      if (reflectionCount > 1)        return obj; // 这里有错误      object retval = Activator.CreateInstance(obj.GetType());      PropertyInfo[] properties = obj.GetType().GetProperties(        BindingFlags.Public | BindingFlags.NonPublic        | BindingFlags.Instance | BindingFlags.Static);      foreach (var property in properties)      {        var propertyValue = property.GetValue(obj, null);        if (propertyValue == null)          continue;        property.SetValue(retval, DeepCopyWithReflection_Second(propertyValue), null);      }      return (T)retval;    }    private static int Add(Dictionary<Type, int> dict, Type key)    {      if (key.Equals(typeof(String)) || key.IsValueType) return 0;      if (!dict.ContainsKey(key))      {        dict.Add(key, 1);        return dict[key];      }      dict[key] += 1;      return dict[key];    }}  

  下面用代码来测试下上面的代码是否已经解决了循环递归的问题,具体的测试代码如下所示:

class Program  {    static void Main(string[] args)    {      //ShallowCopyDemo();      //ListShallowCopyDemo();      DeepCopyDemo();      DeepCopyDemo2();    }    private static void WriteLog(string msg)    {      Console.WriteLine(msg);    }    public static void DeepCopyDemo()    {      DeepCopyDemoClass deepCopyClassA = new DeepCopyDemoClass();      deepCopyClassA.Name = "DeepCopyClassDemo";      deepCopyClassA.pIntArray = new int[] { 1 };      deepCopyClassA.DemoEnum = DemoEnum.EnumA;      deepCopyClassA.Address = new Address() { City = "Shanghai" };      deepCopyClassA.TestB = new TestB() { Property1 = "TestProperty", DeepCopyClass = deepCopyClassA };      // 使用反序列化来实现深拷贝      DeepCopyDemoClass deepCopyClassB = DeepCopyHelper.DeepCopyWithBinarySerialize<DeepCopyDemoClass>(deepCopyClassA);      deepCopyClassB.Name = "DeepCopyClassDemoB";      WriteLog(string.Format("  Name->[A:{0}] [B:{1}]", deepCopyClassA.Name, deepCopyClassB.Name));      deepCopyClassB.pIntArray[0] = 2;      WriteLog(string.Format("  intArray->[A:{0}] [B:{1}]", deepCopyClassA.pIntArray[0], deepCopyClassB.pIntArray[0]));      deepCopyClassB.Address = new Address() { City = "Beijing" };      WriteLog(string.Format("  Addressstruct->[A: {0}] [B: {1}]", deepCopyClassA.Address.City, deepCopyClassB.Address.City));      deepCopyClassB.DemoEnum = DemoEnum.EnumB;      WriteLog(string.Format("  DemoEnum->[A: {0}] [B: {1}]", deepCopyClassA.DemoEnum, deepCopyClassB.DemoEnum));      deepCopyClassB.TestB.Property1 = "TestPropertyB";      WriteLog(string.Format("  Property1->[A:{0}] [B:{1}]", deepCopyClassA.TestB.Property1, deepCopyClassB.TestB.Property1));      WriteLog(string.Format("  TestB.DeepCopyClass.Name->[A:{0}] [B:{1}]", deepCopyClassA.TestB.DeepCopyClass.Name, deepCopyClassB.TestB.DeepCopyClass.Name));      Console.WriteLine();    }    public static void DeepCopyDemo2()    {      DeepCopyDemoClass deepCopyClassA = new DeepCopyDemoClass();      deepCopyClassA.Name = "DeepCopyClassDemo";      deepCopyClassA.pIntArray = new int[] { 1, 2 };      deepCopyClassA.DemoEnum = DemoEnum.EnumA;      deepCopyClassA.Address = new Address() { City = "Shanghai" };      deepCopyClassA.TestB = new TestB() { Property1 = "TestProperty", DeepCopyClass = deepCopyClassA };      // 使用反射来完成深拷贝      DeepCopyDemoClass deepCopyClassB = DeepCopyHelper.DeepCopyWithReflection_Second<DeepCopyDemoClass>(deepCopyClassA);      //DeepCopyDemoClass deepCopyClassB = DeepCopyHelper.DeepCopyWithReflection<DeepCopyDemoClass>(deepCopyClassA);      deepCopyClassB.Name = "DeepCopyClassDemoB";      WriteLog(string.Format("  Name->[A:{0}] [B:{1}]", deepCopyClassA.Name, deepCopyClassB.Name));      deepCopyClassB.pIntArray[0] = 2;      WriteLog(string.Format("  intArray->[A:{0}] [B:{1}]", deepCopyClassA.pIntArray[0], deepCopyClassB.pIntArray[0]));      deepCopyClassB.Address = new Address() { City = "Beijing" };      WriteLog(string.Format("  Addressstruct->[A: {0}] [B: {1}]", deepCopyClassA.Address.City, deepCopyClassB.Address.City));      deepCopyClassB.DemoEnum = DemoEnum.EnumB;      WriteLog(string.Format("  DemoEnum->[A: {0}] [B: {1}]", deepCopyClassA.DemoEnum, deepCopyClassB.DemoEnum));      deepCopyClassB.TestB.Property1 = "TestPropertyB";      WriteLog(string.Format("  Property1->[A:{0}] [B:{1}]", deepCopyClassA.TestB.Property1, deepCopyClassB.TestB.Property1));      WriteLog(string.Format("  TestB.DeepCopyClass.Name->[A:{0}] [B:{1}]", deepCopyClassA.TestB.DeepCopyClass.Name, deepCopyClassB.TestB.DeepCopyClass.Name));      Console.ReadKey();    }  }  

  此时的运行结果如下图所示:

  刚开始看到这样的运行结果,开心地以为已经解决了循环递归的问题了,因为此时结果成功运行出来了,没有了StackOverflower的错误了。但是仔细一看,反序列化和反射完成的深拷贝的运行结果不一样,如上图中红色圈出来的部分。显然,反序列化的结果是没有错误的,显然目前实现的反射代码还是有问题的。接下来就是思考了。为什么上面反射的代码不正确呢?

  仔细分析DeepCopyWithReflection_Second中的代码,发现下面代码红色部分是错误的:

int reflectionCount = Add(typereflectionCountDic, obj.GetType());      if (reflectionCount > 1)        return obj; // 是错误的

  对DeepCopyWithReflection_Second方法仔细分析,在对TestB进行反射时,当反射到DeepCopyClass属性时,此时会递归调用DeepCopyWithReflection_Second方法,此时在typereflectionCountDic发现DeepCopyDemoClass已经被反射了,则直接返回,这样分析好像没什么错误,但是此时返回的是deepCopyClassA对象,但是我们需要返回的是deepCopyClassB对象,即此时deepCopyClassB对象的内存结构如下图所示:

 

  而我们其实需要deepCopyClassB对象的内存结构如下图所示:

  既然找到了DeepCopyWithReflection_Second的错误原因,那我们就要解决了。上面说我们返回的应该是deepCopyClassB对象,而我们怎么得到创建的deepCopyClassB对象呢?这里我就想能不能用一个变量来保存一开始通过CreateInstance方法创建的deepCopyClassB对象呢?验证想法最好的办法就是代码了,这样我就按照这个思路对DeepCopyWithReflection_Second又进行一次改进,最终的代码如下所示:

 public static T DeepCopyWithReflection_Third<T>(T obj)    {      Type type = obj.GetType();      // 如果是字符串或值类型则直接返回      if (obj is string || type.IsValueType) return obj;      if (type.IsArray)      {        Type elementType = Type.GetType(type.FullName.Replace("[]", string.Empty));        var array = obj as Array;        Array copied = Array.CreateInstance(elementType, array.Length);        for (int i = 0; i < array.Length; i++)        {          copied.SetValue(DeepCopyWithReflection_Second(array.GetValue(i)), i);        }        return (T)Convert.ChangeType(copied, obj.GetType());      }      int reflectionCount = Add(typereflectionCountDic, obj.GetType());      if (reflectionCount > 1 && obj.GetType() == typeof(DeepCopyDemoClass))        return (T)DeepCopyDemoClasstypeRef; // 返回deepCopyClassB对象      object retval = Activator.CreateInstance(obj.GetType());      if(retval.GetType() == typeof(DeepCopyDemoClass))        DeepCopyDemoClasstypeRef = retval; // 保存一开始创建的DeepCopyDemoClass对象      PropertyInfo[] properties = obj.GetType().GetProperties(        BindingFlags.Public | BindingFlags.NonPublic        | BindingFlags.Instance | BindingFlags.Static);      foreach (var property in properties)      {        var propertyValue = property.GetValue(obj, null);        if (propertyValue == null)          continue;        property.SetValue(retval, DeepCopyWithReflection_Third(propertyValue), null);      }      return (T)retval;    }

  下面我用DeepCopyWithReflection_Third方法来测试下,具体的测试代码如下所示:

 class Program  {    static void Main(string[] args)    {      //ShallowCopyDemo();      //ListShallowCopyDemo();      DeepCopyDemo();      DeepCopyDemo2();    }     private static void WriteLog(string msg)    {      Console.WriteLine(msg);    }    public static void DeepCopyDemo()    {      DeepCopyDemoClass deepCopyClassA = new DeepCopyDemoClass();      deepCopyClassA.Name = "DeepCopyClassDemo";      deepCopyClassA.pIntArray = new int[] { 1 };      deepCopyClassA.DemoEnum = DemoEnum.EnumA;      deepCopyClassA.Address = new Address() { City = "Shanghai" };      deepCopyClassA.TestB = new TestB() { Property1 = "TestProperty", DeepCopyClass = deepCopyClassA };      // 使用反序列化来实现深拷贝      DeepCopyDemoClass deepCopyClassB = DeepCopyHelper.DeepCopyWithBinarySerialize<DeepCopyDemoClass>(deepCopyClassA);      deepCopyClassB.Name = "DeepCopyClassDemoB";      WriteLog(string.Format("  Name->[A:{0}] [B:{1}]", deepCopyClassA.Name, deepCopyClassB.Name));      deepCopyClassB.pIntArray[0] = 2;      WriteLog(string.Format("  intArray->[A:{0}] [B:{1}]", deepCopyClassA.pIntArray[0], deepCopyClassB.pIntArray[0]));      deepCopyClassB.Address = new Address() { City = "Beijing" };      WriteLog(string.Format("  Addressstruct->[A: {0}] [B: {1}]", deepCopyClassA.Address.City, deepCopyClassB.Address.City));      deepCopyClassB.DemoEnum = DemoEnum.EnumB;      WriteLog(string.Format("  DemoEnum->[A: {0}] [B: {1}]", deepCopyClassA.DemoEnum, deepCopyClassB.DemoEnum));      deepCopyClassB.TestB.Property1 = "TestPropertyB";      WriteLog(string.Format("  Property1->[A:{0}] [B:{1}]", deepCopyClassA.TestB.Property1, deepCopyClassB.TestB.Property1));      WriteLog(string.Format("  TestB.DeepCopyClass.Name->[A:{0}] [B:{1}]", deepCopyClassA.TestB.DeepCopyClass.Name, deepCopyClassB.TestB.DeepCopyClass.Name));      Console.WriteLine();    }    public static void DeepCopyDemo2()    {      DeepCopyDemoClass deepCopyClassA = new DeepCopyDemoClass();      deepCopyClassA.Name = "DeepCopyClassDemo";      deepCopyClassA.pIntArray = new int[] { 1, 2 };      deepCopyClassA.DemoEnum = DemoEnum.EnumA;      deepCopyClassA.Address = new Address() { City = "Shanghai" };      deepCopyClassA.TestB = new TestB() { Property1 = "TestProperty", DeepCopyClass = deepCopyClassA };      // 使用反射来完成深拷贝      DeepCopyDemoClass deepCopyClassB = DeepCopyHelper.DeepCopyWithReflection_Third<DeepCopyDemoClass>(deepCopyClassA);      //DeepCopyDemoClass deepCopyClassB = DeepCopyHelper.DeepCopyWithReflection<DeepCopyDemoClass>(deepCopyClassA);      deepCopyClassB.Name = "DeepCopyClassDemoB";      WriteLog(string.Format("  Name->[A:{0}] [B:{1}]", deepCopyClassA.Name, deepCopyClassB.Name));      deepCopyClassB.pIntArray[0] = 2;      WriteLog(string.Format("  intArray->[A:{0}] [B:{1}]", deepCopyClassA.pIntArray[0], deepCopyClassB.pIntArray[0]));      deepCopyClassB.Address = new Address() { City = "Beijing" };      WriteLog(string.Format("  Addressstruct->[A: {0}] [B: {1}]", deepCopyClassA.Address.City, deepCopyClassB.Address.City));      deepCopyClassB.DemoEnum = DemoEnum.EnumB;      WriteLog(string.Format("  DemoEnum->[A: {0}] [B: {1}]", deepCopyClassA.DemoEnum, deepCopyClassB.DemoEnum));      deepCopyClassB.TestB.Property1 = "TestPropertyB";      WriteLog(string.Format("  Property1->[A:{0}] [B:{1}]", deepCopyClassA.TestB.Property1, deepCopyClassB.TestB.Property1));      WriteLog(string.Format("  TestB.DeepCopyClass.Name->[A:{0}] [B:{1}]", deepCopyClassA.TestB.DeepCopyClass.Name, deepCopyClassB.TestB.DeepCopyClass.Name));      Console.ReadKey();    }}

  此时的运行结果如下图示所示:

  

  从上面的测试结果可以看出,此时深拷贝的反射实现方法基本上没什么问题了。这个方法也同时解决了相互引用对象的循环递归问题。

五、总结

  到这里,该文章的内容就结束。这里主要记录下自己在一次面试过程中遇到问题的一次总结,从中可以看出,反射进行深拷贝会有很多其他的问题,所以平时还是建议大家使用序列化的形式来进行深拷贝。

  最后附上本文所有源码下载:DeepCopy.zip