Clon Profundo con Expresión.Nuevos y Árboles de Expresión

c# deep-copy expression-trees

Pregunta

Tengo dos interfaces generadas IPerson y IAddress .

Sin embargo, he definido las interfaces de propiedades que se heredan de esas interfaces base

Interfaces

public interface IPerson_Name : IPerson { String Name{get;set;}}

public interface IPerson_Addresses : IPerson
{
    ICollection<IAddress> Addresses{ get; set; }
    IAddress NewAddress();
}
public interface IAddress_Line1 : IAddress
{
    String Line1 { get; set; }
}

Luego tengo dos implementaciones de cada una de las interfaces base.

Implementación

public class Person : IPerson
{
    public String Name { get; set; }
    public ICollection<Address> Addresses { get; set; }
}
public class PersonPoco : IPerson_Name, IPerson_Addresses
{
    public string Name { get; set; }
    public ICollection<IAddress> Addresses { get; set; }
    public IAddress NewAddress()
    {
        return new AddressPoco();
    }
}
public class Address : IAddress
{
    public String Line1 { get; set; }
}
public class AddressPoco : IAddress_Line1
{
    public String Line1 { get; set; }
}

Estoy tratando de construir árboles de expresión para convertir entre PersonPoco y Person, así como cualquier otra IPerson.

Estoy creando una función CopyTo como tal.

Copiar Extenstion

public static class IPersonExt
{
    public static IQueryable<TDest> CopyTo<TSrc,TDest>(this IQueryable<TSrc> persons) 
        where TSrc : IPerson, new()
        where TDest: IPerson, new()
    {

        var innerLambda = (LambdaExpression)CopyTo(typeof (TSrc), typeof (TDest));
        var copyExpr = Expression.Lambda<Func<TSrc, TDest>>(innerLambda.Body, innerLambda.Parameters);
        return persons.Select(copyExpr);
    }
    internal static LambdaExpression CopyTo(Type tSrc, Type tDest)
    {
        var dest = Activator.CreateInstance(tDest);
        var personparam = Expression.Parameter(tSrc);

        var destNewExpr = Expression.New(tDest);
        var memberbindings = new List<MemberBinding>();

        IPerson_Name destName;
        IPerson_Name srcName;
        if ((tDest.IsInstanceOfType(typeof(IPerson_Name)) || tDest.IsInstanceOfType(typeof(Person))) &&
            (tSrc.IsInstanceOfType(typeof(IPerson_Name)) || tSrc.IsInstanceOfType(typeof(Person))))
        {
            memberbindings.Add(Expression.Bind(tDest.GetProperty("Name"), Expression.Property(personparam, "Name")));
        }

        var toEntityParameterExpression = Expression.MemberInit(destNewExpr, memberbindings);

        return Expression.Lambda(
                toEntityParameterExpression,
                personparam
            );
    }
}

Mi intención es guardar el resultado compilado para cada conversión de implementación a conversión de IPerson y IAddress.

Si quieres más información sobre mis intenciones ve esta pregunta.

Editar

Obtuve el parámetro base copiando a una nueva versión. Está funcionando hasta ahora para propiedades básicas. He actualizado el código de arriba

Respuesta popular

EDITAR: Aparentemente, linq para entidades no puede entender las llamadas de método en estas expresiones. así que esto no es de ayuda.

Aquí hay una esencia

Interfaz que implementa la siguiente interfaz podrá copiar las propiedades de sus interfaces comunes.

public interface IEntity
{
}

public interface IEntityObject : IEntity
{
}

public interface IEntityCollection : IEntity
{
}

public interface IEntityProperty : IEntity
{
}

Luego, para cada propiedad de una entidad, necesita crear una interfaz

public interface IThing:IEntity{}
public interface IThing_Property: IThing, IEntityProperty
{
    int SimpleProperty{get;set;}
}
public interface IThing_ComplexProperty: IThing, IEntityObject{}
public interface IThing_ComplexProperty<T> : IEntity_ComplexProperty where T:class, IEntity,new()
{
   T SomeProperty{get;set;}
}
public interface IThing_CollectionProperty: IThing, IEntityCollection{}
public interface IThing_CollectionProperty<T> :IEntity_CollectionProperty where T:class, IEntity,new()
{
   IEnumerable<T> SomeCollectionProperty{get;set;}
}

Ahora si lo haces

IQueryable<SomeThingImpl> x;
IQueryable<SomeOtherThingImpl> y = x.CopyTo<SomeThingImpl,SomeOtherThingImpl>()

No me habrán llamado hasta que enumere.

Además, si los tipos genéricos comparten alguna interfaz de IEntity, también se copiarán.

Para una implementación más completa aquí hay otra idea

Así es como se ven las clases

public static class CopyToExt
{
    private static readonly ConcurrentDictionary<Type, LambdaExpression> expressions;
    private static readonly ConcurrentDictionary<Type, Object> funcs;
    private static readonly ConcurrentDictionary<Type, LambdaExpression> mergeStackExpr;
    private static ConcurrentDictionary<Type, Object> mergeStackFunc;
    public static MethodInfo AsQueryableMethod;
    public static MethodInfo SelectMethod;
    public static MethodInfo ToListMethod;
    public static MethodInfo CopyToMethod;
    public static MethodInfo AddMergeMethod;
    public static MethodInfo CreateMergeMethod;
    public static MethodInfo TryCopyMethod;


    static CopyToExt()
    {

        mergeStackExpr = new ConcurrentDictionary<Type, LambdaExpression>(new Dictionary<Type, LambdaExpression>());
        foreach (MethodInfo m in typeof(Queryable).GetMethods().Where(m => m.Name == "Select"))
            foreach (ParameterInfo p in m.GetParameters().Where(p => p.Name.Equals("selector")))
                if (p.ParameterType.GetGenericArguments().Any(x => x.GetGenericArguments().Count() == 2))
                    SelectMethod = (MethodInfo)p.Member;
        foreach (MethodInfo m in typeof(Enumerable).GetMethods().Where(m => m.Name == "ToList"))
            foreach (ParameterInfo p in m.GetParameters().Where(p => p.Name.Equals("source")))
                if (p.ParameterType.GetGenericArguments().Count() == 1)
                    ToListMethod = (MethodInfo)p.Member;
        foreach (MethodInfo m in typeof(Queryable).GetMethods().Where(m => m.Name == "AsQueryable"))
            foreach (ParameterInfo p in m.GetParameters().Where(p => p.Name.Equals("source")))
                if (p.ParameterType.GetGenericArguments().Count() == 1)
                    AsQueryableMethod = (MethodInfo)p.Member;

        CreateMergeMethod = typeof(CopyToExt).GetMethods().First(m => m.Name == "CreateMergeStack");
        AddMergeMethod = typeof(MergeStack).GetMethods().First(m => m.Name == "AddReturnOrCreateAddReturn");
        TryCopyMethod = typeof(MergeStack).GetMethods().First(m => m.Name == "TryCopy");
    }

    public static IQueryable<TDest> CopyTo<TSrc, TDest>(this IQueryable<TSrc> queryable)
        where TSrc : class, IEntity
        where TDest : class, IEntity
    {
        var copyExpr = CreateTryCopy<TSrc, TDest>();
        var ms = CreateMergeStack<TSrc>();
        return queryable.Select(ms).Select(copyExpr);
    }

    public static IEnumerable<TDest> CopyTo<TSrc, TDest>(this IEnumerable<TSrc> queryable)
        where TSrc : class, IEntity
        where TDest : class, IEntity
    {
        return queryable.AsQueryable().CopyTo<TSrc, TDest>().AsEnumerable();
    }


    public static Expression<Func<TSrc, Stackholder<TSrc>>> CreateMergeStack<TSrc>()
    {
        return mergeStackExpr.GetOrAdd(typeof(TSrc), (type) =>
        {
            var shtype = typeof(Stackholder<TSrc>);
            var parm = Expression.Parameter(typeof(TSrc));
            var destNewExpr = Expression.New(shtype);
            var methodcall = Expression.Call(null,
                CopyToExt.AddMergeMethod);

            var memInit = Expression.MemberInit(destNewExpr,
                Expression.Bind(shtype.GetField("Src"), parm),
                Expression.Bind(shtype.GetField("Ms"), methodcall));
            return Expression.Lambda<Func<TSrc, Stackholder<TSrc>>>(memInit, parm);
        }) as Expression<Func<TSrc, Stackholder<TSrc>>>;
    }

    public static Expression<Func<Stackholder<TSrc>, TDest>> CreateTryCopy<TSrc, TDest>()
    {

        var shtype = typeof(Stackholder<TSrc>);
        var parentParam = Expression.Parameter(shtype);
        var SrcExpr = Expression.PropertyOrField(parentParam, "Src");
        var MSExpr = Expression.PropertyOrField(parentParam, "Ms");
        var tcMethod = Expression.Call(MSExpr,
            TryCopyMethod.MakeGenericMethod(new Type[] { typeof(TSrc), typeof(TDest) }),
            SrcExpr);
        return Expression.Lambda<Func<Stackholder<TSrc>, TDest>>(tcMethod, parentParam);
    }

    internal static bool Impliments(this Type type, Type inheritedType)
    {
        return (type.IsSubclassOf(inheritedType) || type.GetInterface(inheritedType.FullName) != null);
    }

    internal static bool Impliments<T>(this Type type, Type inheritedType = null)
    {
        return type.Impliments(typeof(T));
    }

    private static ConcurrentDictionary<Type, Object> AssignDict =
        new ConcurrentDictionary<Type, Object>(new Dictionary<Type, Object>());
    internal static Func<TSrc, TDest, MergeStack, TDest> Assign<TSrc, TDest>()
    {
        return (Func<TSrc, TDest, MergeStack, TDest>) AssignDict.GetOrAdd(typeof (Func<TSrc, TDest>), (indexType) =>
        {
            var tSrc = typeof (TSrc);
            var tDest = typeof (TDest);
            var srcEntityInterfaces = tSrc.GetInterfaces().Where(x => x.Impliments<IEntity>());
            var destEntityInterfaces = tDest.GetInterfaces().Where(x => x.Impliments<IEntity>());
            var srcParam = Expression.Parameter(tSrc);
            var destParam = Expression.Parameter(tDest);
            var MSExpr = Expression.Parameter(typeof (MergeStack));


            var common = destEntityInterfaces.Intersect(srcEntityInterfaces);

            var memberbindings = common.Where(x => x.Impliments<IEntityProperty>())
                .Select(type => type.GetProperties().First())
                .Select(
                    prop =>
                        Expression.Assign(Expression.Property(destParam, prop.Name),
                            Expression.Property(srcParam, prop.Name)))
                .Cast<Expression>().ToList();


            foreach (var type in common.Where(x => x.Impliments<IEntityObject>()))
            {
                var destSubType = destEntityInterfaces.First(x => x.Impliments(type))
                    .GetGenericArguments()
                    .First();
                var srcSubType = srcEntityInterfaces.First(x => x.Impliments(type))
                    .GetGenericArguments()
                    .First();
                var dProp = destEntityInterfaces.First(x => x.Impliments(type)).GetProperties().First();
                var sProp = srcEntityInterfaces.First(x => x.Impliments(type)).GetProperties().First();

                var tcParam = Expression.Parameter(srcSubType);
                var tcMethod = Expression.Call(MSExpr,
                    TryCopyMethod.MakeGenericMethod(new Type[] {srcSubType, destSubType}),
                    tcParam);
                LambdaExpression mergeLambda = Expression.Lambda(tcMethod, tcParam);

                MemberExpression memberExpression = Expression.Property(srcParam, sProp.Name);
                InvocationExpression invocationExpression = Expression.Invoke(mergeLambda,
                    Expression.Property(srcParam, sProp.Name));
                var check = Expression.Condition(
                    Expression.MakeBinary(ExpressionType.NotEqual, memberExpression,
                        Expression.Constant(null, sProp.PropertyType)), invocationExpression,
                    Expression.Constant(null, invocationExpression.Type));
                BinaryExpression binaryExpression = Expression.Assign(Expression.Property(destParam, dProp.Name),
                    check);
                memberbindings.Add(binaryExpression);
            }

            foreach (var type in common.Where(x => x.Impliments<IEntityCollection>()))
            {
                var destSubType = destEntityInterfaces.First(x => x.Impliments(type))
                    .GetGenericArguments()
                    .First();
                var srcSubType = srcEntityInterfaces.First(x => x.Impliments(type))
                    .GetGenericArguments()
                    .First();
                var dProp = destEntityInterfaces.First(x => x.Impliments(type)).GetProperties().First();
                var sProp = srcEntityInterfaces.First(x => x.Impliments(type)).GetProperties().First();

                var tcParam = Expression.Parameter(srcSubType);
                var tcMethod = Expression.Call(MSExpr,
                    TryCopyMethod.MakeGenericMethod(new Type[] {srcSubType, destSubType}),
                    tcParam);
                LambdaExpression mergeLambda = Expression.Lambda(tcMethod, tcParam);

                var memberExpression = Expression.Property(srcParam, sProp.Name);

                var selectExpr = Expression.Call(null,
                    AsQueryableMethod.MakeGenericMethod(new Type[] {srcSubType}),
                    new Expression[] {memberExpression});
                selectExpr = Expression.Call(null,
                    CopyToExt.SelectMethod.MakeGenericMethod(new Type[] {srcSubType, destSubType}),
                    new Expression[] {selectExpr, mergeLambda});
                selectExpr = Expression.Call(null,
                    CopyToExt.ToListMethod.MakeGenericMethod(new Type[] {destSubType}),
                    new Expression[] {selectExpr});


                var check = Expression.Condition(
                    Expression.MakeBinary(ExpressionType.NotEqual, memberExpression,
                        Expression.Constant(null, sProp.PropertyType)), selectExpr,
                    Expression.Constant(null, selectExpr.Type));

                memberbindings.Add(Expression.Assign(Expression.Property(destParam, dProp.Name), check));
            }
            memberbindings.Add(destParam);
            return
                Expression.Lambda<Func<TSrc, TDest, MergeStack, TDest>>(Expression.Block(memberbindings),
                    new ParameterExpression[] {srcParam, destParam, MSExpr}).Compile();
        });
    }
}

public class Stackholder<TSrc>
{
    public MergeStack Ms;
    public TSrc Src;
}
public class MergeStack
{
    private static ConcurrentDictionary<Thread, MergeStack> StackDict = new ConcurrentDictionary<Thread, MergeStack>(new Dictionary<Thread, MergeStack>());
    private readonly Dictionary<Type, Dictionary<Object, Object>> _mergeObjDict = new Dictionary<Type, Dictionary<object, object>>();

    public static MergeStack AddReturnOrCreateAddReturn()
    {
        return StackDict.GetOrAdd(Thread.CurrentThread, (x) => new MergeStack() { });
    }

    public TDest TryCopy<TSrc, TDest>(TSrc Src)
        where TSrc : class, IEntity
        where TDest : class, IEntity, new()
    {
        if (Src == null) return null;
        var objToIndex = new TDest();
        Dictionary<object, object> objToObj;
        if (!_mergeObjDict.ContainsKey(objToIndex.GetType()))
        {
            objToObj = new Dictionary<object, object>();
            _mergeObjDict.Add(objToIndex.GetType(), objToObj);
        }
        else
        {
            objToObj = _mergeObjDict[objToIndex.GetType()];
        }
        if (!objToObj.ContainsKey(Src))
        {
            objToObj.Add(Src, objToIndex);
            return CopyToExt.Assign<TSrc, TDest>()(Src, objToIndex, this);
        }
        return objToObj[Src] as TDest;

    }

}

Aquí hay un archivo de plantilla de texto para generar dichas clases a partir de un diagrama EF



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Licencia bajo: CC-BY-SA with attribution
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