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?
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
我更喜欢复制构造函数而不是克隆。意图更加明确。
其他回答
这将把一个对象的所有可读写财产复制到另一个对象。
public class PropertyCopy<TSource, TTarget>
where TSource: class, new()
where TTarget: class, new()
{
public static TTarget Copy(TSource src, TTarget trg, params string[] properties)
{
if (src==null) return trg;
if (trg == null) trg = new TTarget();
var fulllist = src.GetType().GetProperties().Where(c => c.CanWrite && c.CanRead).ToList();
if (properties != null && properties.Count() > 0)
fulllist = fulllist.Where(c => properties.Contains(c.Name)).ToList();
if (fulllist == null || fulllist.Count() == 0) return trg;
fulllist.ForEach(c =>
{
c.SetValue(trg, c.GetValue(src));
});
return trg;
}
}
这是你使用它的方式:
var cloned = Utils.PropertyCopy<TKTicket, TKTicket>.Copy(_tmp, dbsave,
"Creation",
"Description",
"IdTicketStatus",
"IdUserCreated",
"IdUserInCharge",
"IdUserRequested",
"IsUniqueTicketGenerated",
"LastEdit",
"Subject",
"UniqeTicketRequestId",
"Visibility");
或复制所有内容:
var cloned = Utils.PropertyCopy<TKTicket, TKTicket>.Copy(_tmp, dbsave);
对于克隆过程,可以先将对象转换为字节数组,然后再转换回对象。
public static class Extentions
{
public static T Clone<T>(this T obj)
{
byte[] buffer = BinarySerialize(obj);
return (T)BinaryDeserialize(buffer);
}
public static byte[] BinarySerialize(object obj)
{
using (var stream = new MemoryStream())
{
var formatter = new BinaryFormatter();
formatter.Serialize(stream, obj);
return stream.ToArray();
}
}
public static object BinaryDeserialize(byte[] buffer)
{
using (var stream = new MemoryStream(buffer))
{
var formatter = new BinaryFormatter();
return formatter.Deserialize(stream);
}
}
}
必须为序列化进程序列化对象。
[Serializable]
public class MyObject
{
public string Name { get; set; }
}
用法:
MyObject myObj = GetMyObj();
MyObject newObj = myObj.Clone();
编辑:项目已停止
如果您想真正克隆到未知类型,可以查看fastclone。
这是基于表达式的克隆,其工作速度比二进制序列化快10倍,并保持完整的对象图完整性。
这意味着:如果多次引用层次结构中的同一对象,克隆也将引用一个实例。
不需要对正在克隆的对象进行接口、属性或任何其他修改。
我更喜欢复制构造函数而不是克隆。意图更加明确。
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;
}
}