Deep Clone avec Expression.New et Arbres d'expression

c# deep-copy expression-trees

Question

J'ai deux interfaces IPerson et IAddress .

Cependant, j'ai défini des interfaces de propriété qui héritent de ces interfaces de base

Des 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; }
}

Ensuite, j'ai deux implémentations de chacune des interfaces de base

la mise en oeuvre

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; }
}

J'essaie de construire des arbres d'expression pour convertir entre PersonPoco et Person ainsi que tout autre IPerson

Je crée une fonction CopyTo en tant que telle.

Copie 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
            );
    }
}

Mon intention est de sauvegarder la sortie compilée pour chaque conversion d'une implémentation à l'autre d'IPerson et d'IAddress.

Si vous voulez plus d'informations sur mes intentions voir cette question

modifier

J'ai copié le paramètre de base dans une nouvelle version. Cela fonctionne jusqu'à présent pour les propriétés de base. J'ai mis à jour le code ci-dessus

Réponse populaire

EDIT: Apparemment, linq aux entités ne peut pas comprendre les appels de méthodes dans ces expressions. donc ce n'est pas une aide.

Voici un résumé

L'interface qui implémente l'interface suivante sera capable de copier les propriétés de leurs interfaces communes.

public interface IEntity
{
}

public interface IEntityObject : IEntity
{
}

public interface IEntityCollection : IEntity
{
}

public interface IEntityProperty : IEntity
{
}

Ensuite, pour chaque propriété d'une entité, vous devez créer une interface.

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;}
}

Maintenant si tu le fais

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

Je n'aurai pas encore été appelé avant que cela ne soit énuméré.

De même, si les types génériques partagent des interfaces IEntity, ils seront également copiés.

Pour une mise en œuvre plus complète, voici un autre point essentiel

Voici à quoi ressemblent les cours

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;

    }

}

Voici un fichier de modèle de texte pour générer lesdites classes à partir d'un diagramme EF



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