我想做一些事情，比如：
MyObject myObj = GetMyObj(); // Create and fill a new object
MyObject newObj = myObj.Clone();
然后对未反映在原始对象中的新对象进行更改。
我通常不需要这个功能，所以当有必要时，我会创建一个新对象，然后单独复制每个属性，但这总是让我觉得有更好或更优雅的方法来处理这种情况。
如何克隆或深度复制对象，以便在原始对象中不反映任何更改的情况下修改克隆的对象？
当前回答
我已经创建了一个可接受答案的版本，该版本同时适用于“[Serializable]”和“[DataContract]”。我写它已经有一段时间了，但如果我没有记错，[DataContract]需要一个不同的序列化程序。
需要System、System.IO、System.Runtime.Serialization、System.Runtime.Serialization.Formatters.Binary、System.Xml；
public static class ObjectCopier
{
/// <summary>
/// Perform a deep Copy of an object that is marked with '[Serializable]' or '[DataContract]'
/// </summary>
/// <typeparam name="T">The type of object being copied.</typeparam>
/// <param name="source">The object instance to copy.</param>
/// <returns>The copied object.</returns>
public static T Clone<T>(T source)
{
if (typeof(T).IsSerializable == true)
{
return CloneUsingSerializable<T>(source);
}
if (IsDataContract(typeof(T)) == true)
{
return CloneUsingDataContracts<T>(source);
}
throw new ArgumentException("The type must be Serializable or use DataContracts.", "source");
}
/// <summary>
/// Perform a deep Copy of an object that is marked with '[Serializable]'
/// </summary>
/// <remarks>
/// Found on http://stackoverflow.com/questions/78536/cloning-objects-in-c-sharp
/// Uses code found on CodeProject, which allows free use in third party apps
/// - http://www.codeproject.com/KB/tips/SerializedObjectCloner.aspx
/// </remarks>
/// <typeparam name="T">The type of object being copied.</typeparam>
/// <param name="source">The object instance to copy.</param>
/// <returns>The copied object.</returns>
public static T CloneUsingSerializable<T>(T source)
{
if (!typeof(T).IsSerializable)
{
throw new ArgumentException("The type must be serializable.", "source");
}
// Don't serialize a null object, simply return the default for that object
if (Object.ReferenceEquals(source, null))
{
return default(T);
}
IFormatter formatter = new BinaryFormatter();
Stream stream = new MemoryStream();
using (stream)
{
formatter.Serialize(stream, source);
stream.Seek(0, SeekOrigin.Begin);
return (T)formatter.Deserialize(stream);
}
}
/// <summary>
/// Perform a deep Copy of an object that is marked with '[DataContract]'
/// </summary>
/// <typeparam name="T">The type of object being copied.</typeparam>
/// <param name="source">The object instance to copy.</param>
/// <returns>The copied object.</returns>
public static T CloneUsingDataContracts<T>(T source)
{
if (IsDataContract(typeof(T)) == false)
{
throw new ArgumentException("The type must be a data contract.", "source");
}
// ** Don't serialize a null object, simply return the default for that object
if (Object.ReferenceEquals(source, null))
{
return default(T);
}
DataContractSerializer dcs = new DataContractSerializer(typeof(T));
using(Stream stream = new MemoryStream())
{
using (XmlDictionaryWriter writer = XmlDictionaryWriter.CreateBinaryWriter(stream))
{
dcs.WriteObject(writer, source);
writer.Flush();
stream.Seek(0, SeekOrigin.Begin);
using (XmlDictionaryReader reader = XmlDictionaryReader.CreateBinaryReader(stream, XmlDictionaryReaderQuotas.Max))
{
return (T)dcs.ReadObject(reader);
}
}
}
}
/// <summary>
/// Helper function to check if a class is a [DataContract]
/// </summary>
/// <param name="type">The type of the object to check.</param>
/// <returns>Boolean flag indicating if the class is a DataContract (true) or not (false) </returns>
public static bool IsDataContract(Type type)
{
object[] attributes = type.GetCustomAttributes(typeof(DataContractAttribute), false);
return attributes.Length == 1;
}
}
其他回答
我已经创建了一个可接受答案的版本，该版本同时适用于“[Serializable]”和“[DataContract]”。我写它已经有一段时间了，但如果我没有记错，[DataContract]需要一个不同的序列化程序。
需要System、System.IO、System.Runtime.Serialization、System.Runtime.Serialization.Formatters.Binary、System.Xml；
public static class ObjectCopier
{
/// <summary>
/// Perform a deep Copy of an object that is marked with '[Serializable]' or '[DataContract]'
/// </summary>
/// <typeparam name="T">The type of object being copied.</typeparam>
/// <param name="source">The object instance to copy.</param>
/// <returns>The copied object.</returns>
public static T Clone<T>(T source)
{
if (typeof(T).IsSerializable == true)
{
return CloneUsingSerializable<T>(source);
}
if (IsDataContract(typeof(T)) == true)
{
return CloneUsingDataContracts<T>(source);
}
throw new ArgumentException("The type must be Serializable or use DataContracts.", "source");
}
/// <summary>
/// Perform a deep Copy of an object that is marked with '[Serializable]'
/// </summary>
/// <remarks>
/// Found on http://stackoverflow.com/questions/78536/cloning-objects-in-c-sharp
/// Uses code found on CodeProject, which allows free use in third party apps
/// - http://www.codeproject.com/KB/tips/SerializedObjectCloner.aspx
/// </remarks>
/// <typeparam name="T">The type of object being copied.</typeparam>
/// <param name="source">The object instance to copy.</param>
/// <returns>The copied object.</returns>
public static T CloneUsingSerializable<T>(T source)
{
if (!typeof(T).IsSerializable)
{
throw new ArgumentException("The type must be serializable.", "source");
}
// Don't serialize a null object, simply return the default for that object
if (Object.ReferenceEquals(source, null))
{
return default(T);
}
IFormatter formatter = new BinaryFormatter();
Stream stream = new MemoryStream();
using (stream)
{
formatter.Serialize(stream, source);
stream.Seek(0, SeekOrigin.Begin);
return (T)formatter.Deserialize(stream);
}
}
/// <summary>
/// Perform a deep Copy of an object that is marked with '[DataContract]'
/// </summary>
/// <typeparam name="T">The type of object being copied.</typeparam>
/// <param name="source">The object instance to copy.</param>
/// <returns>The copied object.</returns>
public static T CloneUsingDataContracts<T>(T source)
{
if (IsDataContract(typeof(T)) == false)
{
throw new ArgumentException("The type must be a data contract.", "source");
}
// ** Don't serialize a null object, simply return the default for that object
if (Object.ReferenceEquals(source, null))
{
return default(T);
}
DataContractSerializer dcs = new DataContractSerializer(typeof(T));
using(Stream stream = new MemoryStream())
{
using (XmlDictionaryWriter writer = XmlDictionaryWriter.CreateBinaryWriter(stream))
{
dcs.WriteObject(writer, source);
writer.Flush();
stream.Seek(0, SeekOrigin.Begin);
using (XmlDictionaryReader reader = XmlDictionaryReader.CreateBinaryReader(stream, XmlDictionaryReaderQuotas.Max))
{
return (T)dcs.ReadObject(reader);
}
}
}
}
/// <summary>
/// Helper function to check if a class is a [DataContract]
/// </summary>
/// <param name="type">The type of the object to check.</param>
/// <returns>Boolean flag indicating if the class is a DataContract (true) or not (false) </returns>
public static bool IsDataContract(Type type)
{
object[] attributes = type.GetCustomAttributes(typeof(DataContractAttribute), false);
return attributes.Length == 1;
}
}
除了这里的一些精彩答案外，您可以在C#9.0及更高版本中完成以下操作（假设您可以将类转换为记录）：
record Record
{
public int Property1 { get; set; }
public string Property2 { get; set; }
}
然后，只需使用with运算符将一个对象的值复制到新对象。
var object1 = new Record()
{
Property1 = 1,
Property2 = "2"
};
var object2 = object1 with { };
// object2 now has Property1 = 1 & Property2 = "2"
我希望这有助于：）
我将使用下面的简单方法来实现这一点。只需创建一个抽象类和实现方法以再次序列化和反序列化并返回。
public abstract class CloneablePrototype<T>
{
public T DeepCopy()
{
string result = JsonConvert.SerializeObject(this);
return JsonConvert.DeserializeObject<T>(result);
}
}
public class YourClass : CloneablePrototype< YourClass>
…
…
…
然后像这样使用它来创建深度副本。
YourClass newObj = (YourClass)oldObj.DeepCopy();
如果您还需要实现浅层复制方法，则此解决方案也很容易扩展。
只需在抽象类中实现一个新方法。
public T ShallowCopy()
{
return (T)this.MemberwiseClone();
}
在我使用的代码库中，我们有一个来自GitHub项目Burtsev Alexey/net对象深度副本的ObjectExtension.cs文件副本。它已经9岁了。虽然我们后来意识到，对于更大的对象结构来说，它是非常慢的，但它还是有效的。
相反，我们在GitHub项目jpmikkers/Baksteen.Extensions.DeepCopy中找到了ObjectExtension.cs文件的一个分支。以前对大型数据结构的深度复制操作需要大约30分钟，现在感觉几乎是瞬间完成的。
此改进版本包含以下文档：
用于快速对象克隆的C#扩展方法。这是Alexey Burtsev深度复印机的速度优化叉。根据您的使用情况，这将比原始版本快2倍-3倍。它还修复了原始代码中存在的一些错误。与经典的二进制序列化/反序列化深度克隆技术相比，此版本的速度大约快七倍（对象包含的数组越多，加速因子越大）。通过以下技术实现加速：缓存对象反射结果不要深度复制原语或不可变结构&类（例如枚举和字符串）为了提高引用的局部性，处理内部循环中的“快速”维度或多维数组使用编译的lambda表达式调用MemberwiseClone如何使用：使用Baksteen.Extensions.DeepCopy；...var myobject=新建SomeClass（）；...var myclone=myobject.DepCopy（）！；//创建原始对象的新深度副本注意：只有在项目中启用了可为null的引用类型时，才需要感叹号（null原谅运算符）
使用System.Text.Json；
public static class CloneExtensions
{
public static T Clone<T>(this T cloneable) where T : new()
{
var toJson = JsonSerializer.Serialize(cloneable);
return JsonSerializer.Deserialize<T>(toJson);
}
}
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