C#对象拷贝(复制)

直接赋值

将a的引用复制给b，实际操作的是同一个对象，当修改zhangsan的属性时，李四的属性也随之改变，同样lisi的属性修改后，zhangsan的属性也会修改。

案例

Person zhangsan = new Person()
{
    Name = "张三",
    Age = 28
};
Person lisi = new Person()
{
    Name = "李四",
    Age = 29
};
lisi = zhangsan;
Console.WriteLine("zhangsan==Name:{0},Age:{1}", zhangsan.Name,zhangsan.Age);
Console.WriteLine("lisi==Name:{0},Age:{1}", lisi.Name,lisi.Age);
Console.WriteLine("-----------------------修改lisi的属性值-----------------------");
lisi.Name = "李四";
lisi.Age = 30;
Console.WriteLine("zhangsan==Name:{0},Age:{1}", zhangsan.Name, zhangsan.Age);
Console.WriteLine("lisi==Name:{0},Age:{1}", lisi.Name, lisi.Age);

 

利用反射拷贝

• 深拷贝

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。深拷贝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。

深拷贝代码

 public static T DeepCopyByReflect<T>(T obj)
 {
     //如果是字符串或值类型则直接返回
     if (obj == null || (obj is string) || (obj.GetType().IsValueType)) return obj;

     object retval = Activator.CreateInstance(obj.GetType());
     FieldInfo[] fields = obj.GetType().GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static);
     foreach (FieldInfo field in fields)
     {
         try { field.SetValue(retval, DeepCopyByReflect(field.GetValue(obj))); }
         catch { }
     }
     return (T)retval;
}

案例

将张三的对象复制给李四后，修改李四的属性值时，张三的属性值并未改变。

Person zhangsan = new Person()
{
    Name = "张三",
    Age = 28
};
Person lisi = new Person()
{
    Name = "李四",
    Age = 29
};
lisi=DeepCopyByReflect<Person>(zhangsan);
Console.WriteLine("zhangsan==Name:{0},Age:{1}", zhangsan.Name, zhangsan.Age);
Console.WriteLine("lisi==Name:{0},Age:{1}", lisi.Name, lisi.Age);
Console.WriteLine("-----------------------修改lisi的属性值-----------------------");
lisi.Name = "李四";
lisi.Age = 30;
Console.WriteLine("zhangsan==Name:{0},Age:{1}", zhangsan.Name, zhangsan.Age);
Console.WriteLine("lisi==Name:{0},Age:{1}", lisi.Name, lisi.Age);

 

 

• 浅拷贝

和直接赋值一样，仅仅拷贝对象的引用进行拷贝，实际操作的是同一个对象，当修改zhangsan的属性时，李四的属性也随之改变，同样lisi的属性修改后，zhangsan的属性也会修改。

浅拷贝代码

FieldInfo[] fields = typeof(TSource).GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
for (int i = 0; i < fields.Length; i++)
{
    FieldInfo field = fields[i];
    field.SetValue(targetVal, field.GetValue(sourceVal));
}
PropertyInfo[] properties = typeof(TSource).GetProperties(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
for (int i = 0; i < properties.Length; i++)
{
    PropertyInfo property = properties[i];
    property.SetValue(targetVal, property.GetValue(sourceVal, null), null);
}

 案例

Person zhangsan = new Person()
{
    Name = "张三",
    Age = 28
};
Person lisi = new Person()
{
    Name = "李四",
    Age = 29
};
lisi = zhangsan;
Console.WriteLine("zhangsan==Name:{0},Age:{1}", zhangsan.Name,zhangsan.Age);
Console.WriteLine("lisi==Name:{0},Age:{1}", lisi.Name,lisi.Age);
Console.WriteLine("-----------------------修改lisi的属性值-----------------------");
lisi.Name = "李四";
lisi.Age = 30;
ShallowCopy<Person, Person>(lisi,zhangsan);
Console.WriteLine("zhangsan==Name:{0},Age:{1}", zhangsan.Name, zhangsan.Age);
Console.WriteLine("lisi==Name:{0},Age:{1}", lisi.Name, lisi.Age);