最高效率的对象深拷贝通用方法--转转
原文:http://blog.csdn.net/qldsrx/article/details/8265985
using System; using System.Collections.Generic; using System.Linq; using System.Reflection; using System.Reflection.Emit; using System.Text; namespace Care.Common { public static class ObjectCopy { struct Identity { int _hashcode; RuntimeTypeHandle _type; public Identity(int hashcode, RuntimeTypeHandle type) { _hashcode = hashcode; _type = type; } } //缓存对象复制的方法。 static Dictionary<Type, Func<object, Dictionary<Identity, object>, object>> methods1 = new Dictionary<Type, Func<object, Dictionary<Identity, object>, object>>(); static Dictionary<Type, Action<object, Dictionary<Identity, object>, object>> methods2 = new Dictionary<Type, Action<object, Dictionary<Identity, object>, object>>(); static List<FieldInfo> GetSettableFields(Type t) { return t.GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance).ToList(); } static Func<object, Dictionary<Identity, object>, object> CreateCloneMethod1(Type type, Dictionary<Identity, object> objects) { Type tmptype; var fields = GetSettableFields(type); var dm = new DynamicMethod(string.Format("Clone{0}", Guid.NewGuid()), typeof(object), new[] { typeof(object), typeof(Dictionary<Identity, object>) }, true); var il = dm.GetILGenerator(); il.DeclareLocal(type); il.DeclareLocal(type); il.DeclareLocal(typeof(Identity)); if (!type.IsArray) { il.Emit(OpCodes.Newobj, type.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, Type.EmptyTypes, null)); il.Emit(OpCodes.Dup); il.Emit(OpCodes.Stloc_1); il.Emit(OpCodes.Ldloca_S, 2); il.Emit(OpCodes.Ldarg_0); il.Emit(OpCodes.Castclass, type); il.Emit(OpCodes.Dup); il.Emit(OpCodes.Stloc_0); il.Emit(OpCodes.Callvirt, typeof(object).GetMethod("GetHashCode")); il.Emit(OpCodes.Ldtoken, type); il.Emit(OpCodes.Call, typeof(Identity).GetConstructor(BindingFlags.Instance | BindingFlags.Public, null, new[] { typeof(int), typeof(RuntimeTypeHandle) }, null)); il.Emit(OpCodes.Ldarg_1); il.Emit(OpCodes.Ldloc_2); il.Emit(OpCodes.Ldloc_1); il.Emit(OpCodes.Callvirt, typeof(Dictionary<Identity, object>).GetMethod("Add")); foreach (var field in fields) { if (!field.FieldType.IsValueType && field.FieldType != typeof(String)) { //不符合条件的字段,直接忽略,避免报错。 if ((field.FieldType.IsArray && (field.FieldType.GetArrayRank() > 1 || (!(tmptype = field.FieldType.GetElementType()).IsValueType && tmptype != typeof(String) && tmptype.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, Type.EmptyTypes, null) == null))) || (!field.FieldType.IsArray && field.FieldType.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, Type.EmptyTypes, null) == null)) break; il.Emit(OpCodes.Ldloc_1); il.Emit(OpCodes.Ldloc_0); il.Emit(OpCodes.Ldfld, field); il.Emit(OpCodes.Ldarg_1); il.EmitCall(OpCodes.Call, typeof(ObjectCopy).GetMethod("CopyImpl", BindingFlags.NonPublic | BindingFlags.Static).MakeGenericMethod(field.FieldType), null); il.Emit(OpCodes.Stfld, field); } else { il.Emit(OpCodes.Ldloc_1); il.Emit(OpCodes.Ldloc_0); il.Emit(OpCodes.Ldfld, field); il.Emit(OpCodes.Stfld, field); } } for (type = type.BaseType; type != null && type != typeof(object); type = type.BaseType) { //只需要查找基类的私有成员,共有或受保护的在派生类中直接被复制过了。 fields = type.GetFields(BindingFlags.NonPublic | BindingFlags.Instance).ToList(); foreach (var field in fields) { if (!field.FieldType.IsValueType && field.FieldType != typeof(String)) { //不符合条件的字段,直接忽略,避免报错。 if ((field.FieldType.IsArray && (field.FieldType.GetArrayRank() > 1 || (!(tmptype = field.FieldType.GetElementType()).IsValueType && tmptype != typeof(String) && tmptype.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, Type.EmptyTypes, null) == null))) || (!field.FieldType.IsArray && field.FieldType.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, Type.EmptyTypes, null) == null)) break; il.Emit(OpCodes.Ldloc_1); il.Emit(OpCodes.Ldloc_0); il.Emit(OpCodes.Ldfld, field); il.Emit(OpCodes.Ldarg_1); il.EmitCall(OpCodes.Call, typeof(ObjectCopy).GetMethod("CopyImpl", BindingFlags.NonPublic | BindingFlags.Static).MakeGenericMethod(field.FieldType), null); il.Emit(OpCodes.Stfld, field); } else { il.Emit(OpCodes.Ldloc_1); il.Emit(OpCodes.Ldloc_0); il.Emit(OpCodes.Ldfld, field); il.Emit(OpCodes.Stfld, field); } } } } else { Type arraytype = type.GetElementType(); var i = il.DeclareLocal(typeof(int)); var lb1 = il.DefineLabel(); var lb2 = il.DefineLabel(); il.Emit(OpCodes.Ldarg_0); il.Emit(OpCodes.Castclass, type); il.Emit(OpCodes.Dup); il.Emit(OpCodes.Stloc_0); il.Emit(OpCodes.Ldlen); il.Emit(OpCodes.Dup); il.Emit(OpCodes.Ldc_I4_1); il.Emit(OpCodes.Sub); il.Emit(OpCodes.Stloc, i); il.Emit(OpCodes.Newarr, arraytype); il.Emit(OpCodes.Dup); il.Emit(OpCodes.Stloc_1); il.Emit(OpCodes.Ldloca_S, 2); il.Emit(OpCodes.Ldloc_0); il.Emit(OpCodes.Callvirt, typeof(object).GetMethod("GetHashCode")); il.Emit(OpCodes.Ldtoken, type); il.Emit(OpCodes.Call, typeof(Identity).GetConstructor(BindingFlags.Instance | BindingFlags.Public, null, new[] { typeof(int), typeof(RuntimeTypeHandle) }, null)); il.Emit(OpCodes.Ldarg_1); il.Emit(OpCodes.Ldloc_2); il.Emit(OpCodes.Ldloc_1); il.Emit(OpCodes.Callvirt, typeof(Dictionary<Identity, object>).GetMethod("Add")); il.Emit(OpCodes.Ldloc, i); il.Emit(OpCodes.Br, lb1); il.MarkLabel(lb2); il.Emit(OpCodes.Dup); il.Emit(OpCodes.Ldloc, i); il.Emit(OpCodes.Ldloc_0); il.Emit(OpCodes.Ldloc, i); il.Emit(OpCodes.Ldelem, arraytype); if (!arraytype.IsValueType && arraytype != typeof(String)) { il.EmitCall(OpCodes.Call, typeof(ObjectCopy).GetMethod("CopyImpl", BindingFlags.NonPublic | BindingFlags.Static).MakeGenericMethod(arraytype), null); } il.Emit(OpCodes.Stelem, arraytype); il.Emit(OpCodes.Ldloc, i); il.Emit(OpCodes.Ldc_I4_1); il.Emit(OpCodes.Sub); il.Emit(OpCodes.Dup); il.Emit(OpCodes.Stloc, i); il.MarkLabel(lb1); il.Emit(OpCodes.Ldc_I4_0); il.Emit(OpCodes.Clt); il.Emit(OpCodes.Brfalse, lb2); } il.Emit(OpCodes.Ret); return (Func<object, Dictionary<Identity, object>, object>)dm.CreateDelegate(typeof(Func<object, Dictionary<Identity, object>, object>)); } static Action<object, Dictionary<Identity, object>, object> CreateCloneMethod2(Type type, Dictionary<Identity, object> objects) { Type tmptype; var fields = GetSettableFields(type); var dm = new DynamicMethod(string.Format("Copy{0}", Guid.NewGuid()), null, new[] { typeof(object), typeof(Dictionary<Identity, object>), typeof(object) }, true); var il = dm.GetILGenerator(); il.DeclareLocal(type); il.DeclareLocal(type); il.DeclareLocal(typeof(Identity)); if (!type.IsArray) { il.Emit(OpCodes.Ldarg_2); il.Emit(OpCodes.Castclass, type); il.Emit(OpCodes.Stloc_1); il.Emit(OpCodes.Ldarg_0); il.Emit(OpCodes.Castclass, type); il.Emit(OpCodes.Stloc_0); foreach (var field in fields) { if (!field.FieldType.IsValueType && field.FieldType != typeof(String)) { //不符合条件的字段,直接忽略,避免报错。 if ((field.FieldType.IsArray && (field.FieldType.GetArrayRank() > 1 || (!(tmptype = field.FieldType.GetElementType()).IsValueType && tmptype != typeof(String) && tmptype.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, Type.EmptyTypes, null) == null))) || (!field.FieldType.IsArray && field.FieldType.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, Type.EmptyTypes, null) == null)) break; il.Emit(OpCodes.Ldloc_1); il.Emit(OpCodes.Ldloc_0); il.Emit(OpCodes.Ldfld, field); il.Emit(OpCodes.Ldarg_1); il.EmitCall(OpCodes.Call, typeof(ObjectCopy).GetMethod("CopyImpl", BindingFlags.NonPublic | BindingFlags.Static).MakeGenericMethod(field.FieldType), null); il.Emit(OpCodes.Stfld, field); } else { il.Emit(OpCodes.Ldloc_1); il.Emit(OpCodes.Ldloc_0); il.Emit(OpCodes.Ldfld, field); il.Emit(OpCodes.Stfld, field); } } for (type = type.BaseType; type != null && type != typeof(object); type = type.BaseType) { //只需要查找基类的私有成员,共有或受保护的在派生类中直接被复制过了。 fields = type.GetFields(BindingFlags.NonPublic | BindingFlags.Instance).ToList(); foreach (var field in fields) { if (!field.FieldType.IsValueType && field.FieldType != typeof(String)) { //不符合条件的字段,直接忽略,避免报错。 if ((field.FieldType.IsArray && (field.FieldType.GetArrayRank() > 1 || (!(tmptype = field.FieldType.GetElementType()).IsValueType && tmptype != typeof(String) && tmptype.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, Type.EmptyTypes, null) == null))) || (!field.FieldType.IsArray && field.FieldType.GetConstructor(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic, null, Type.EmptyTypes, null) == null)) break; il.Emit(OpCodes.Ldloc_1); il.Emit(OpCodes.Ldloc_0); il.Emit(OpCodes.Ldfld, field); il.Emit(OpCodes.Ldarg_1); il.EmitCall(OpCodes.Call, typeof(ObjectCopy).GetMethod("CopyImpl", BindingFlags.NonPublic | BindingFlags.Static).MakeGenericMethod(field.FieldType), null); il.Emit(OpCodes.Stfld, field); } else { il.Emit(OpCodes.Ldloc_1); il.Emit(OpCodes.Ldloc_0); il.Emit(OpCodes.Ldfld, field); il.Emit(OpCodes.Stfld, field); } } } } else { Type arraytype = type.GetElementType(); var i = il.DeclareLocal(typeof(int)); var lb1 = il.DefineLabel(); var lb2 = il.DefineLabel(); il.Emit(OpCodes.Ldarg_0); il.Emit(OpCodes.Castclass, type); il.Emit(OpCodes.Dup); il.Emit(OpCodes.Stloc_0); il.Emit(OpCodes.Ldlen); il.Emit(OpCodes.Dup); il.Emit(OpCodes.Ldc_I4_1); il.Emit(OpCodes.Sub); il.Emit(OpCodes.Stloc, i); il.Emit(OpCodes.Ldarg_2); il.Emit(OpCodes.Castclass, type); il.Emit(OpCodes.Dup); il.Emit(OpCodes.Stloc_1); il.Emit(OpCodes.Ldloc, i); il.Emit(OpCodes.Br, lb1); il.MarkLabel(lb2); il.Emit(OpCodes.Dup); il.Emit(OpCodes.Ldloc, i); il.Emit(OpCodes.Ldloc_0); il.Emit(OpCodes.Ldloc, i); il.Emit(OpCodes.Ldelem, arraytype); if (!arraytype.IsValueType && arraytype != typeof(String)) { il.EmitCall(OpCodes.Call, typeof(ObjectCopy).GetMethod("CopyImpl", BindingFlags.NonPublic | BindingFlags.Static).MakeGenericMethod(arraytype), null); } il.Emit(OpCodes.Stelem, arraytype); il.Emit(OpCodes.Ldloc, i); il.Emit(OpCodes.Ldc_I4_1); il.Emit(OpCodes.Sub); il.Emit(OpCodes.Dup); il.Emit(OpCodes.Stloc, i); il.MarkLabel(lb1); il.Emit(OpCodes.Ldc_I4_0); il.Emit(OpCodes.Clt); il.Emit(OpCodes.Brfalse, lb2); } il.Emit(OpCodes.Ret); return (Action<object, Dictionary<Identity, object>, object>)dm.CreateDelegate(typeof(Action<object, Dictionary<Identity, object>, object>)); } static T CopyImpl<T>(T source, Dictionary<Identity, object> objects) where T : class { //为空则直接返回null if (source == null) return null; Type type = source.GetType(); Identity id = new Identity(source.GetHashCode(), type.TypeHandle); object result; //如果发现曾经复制过,用之前的,从而停止递归复制。 if (!objects.TryGetValue(id, out result)) { //最后查找对象的复制方法,如果不存在,创建新的。 Func<object, Dictionary<Identity, object>, object> method; if (!methods1.TryGetValue(type, out method)) { method = CreateCloneMethod1(type, objects); methods1.Add(type, method); } result = method(source, objects); } return (T)result; } /// <summary> /// 创建对象深度复制的副本 /// </summary> public static T ToObjectCopy<T>(this T source) where T : class { Type type = source.GetType(); Dictionary<Identity, object> objects = new Dictionary<Identity, object>();//存放内嵌引用类型的复制链,避免构成一个环。 Func<object, Dictionary<Identity, object>, object> method; if (!methods1.TryGetValue(type, out method)) { method = CreateCloneMethod1(type, objects); methods1.Add(type, method); } return (T)method(source, objects); } /// <summary> /// 将source对象的所有属性复制到target对象中,深度复制 /// </summary> public static void ObjectCopyTo<T>(this T source, T target) where T : class { if (target == null) throw new Exception("将要复制的目标未初始化"); Type type = source.GetType(); if (type != target.GetType()) throw new Exception("要复制的对象类型不同,无法复制"); Dictionary<Identity, object> objects = new Dictionary<Identity, object>();//存放内嵌引用类型的复制链,避免构成一个环。 objects.Add(new Identity(source.GetHashCode(), type.TypeHandle), source); Action<object, Dictionary<Identity, object>, object> method; if (!methods2.TryGetValue(type, out method)) { method = CreateCloneMethod2(type, objects); methods2.Add(type, method); } method(source, objects, target); } } }
花了不少精力研究的最高效的通用方法,目前能支持任何带无参数的构造函数的类的深拷贝,一元数组的深拷贝,数组和类的循环嵌套深拷贝,双向链表结构 的类型对象深拷贝,进行对象拷贝过程中,未判断任何附加特性,因此可序列化标志对其无效,即使不可序列化的对象,也可以进行深拷贝。
该方法是最基础的方法,如果需要高级应用,可以自定义特性(Attribute)进行忽略某些字段。
该方法最多用途就是在数据库的实体对象的赋值上面,操作一个临时对象(复制出来),如果中途放弃改动,则直接丢弃对象,不影响原先的对象,否则可将对象复制回去。