Automapper incorrectly displays null List element when condition specified! = Null

Question

Automapper incorrectly displays null List element when condition specified! = Null

There is a problem when I try to display a null list (element) of an object, given that I specified:

.ForAllMembers(opts => opts.Condition((src, dest, srcMember) =>
    srcMember != null
));
cfg.AllowNullCollections = true; // didn't help also

short code example:

gi.PersonList = new List<Person>();
gi.PersonList.Add(new Person { Num = 1, Name = "John", Surname = "Scott" });
GeneralInfo gi2 = new GeneralInfo();
gi2.Qty = 3;

Mapper.Map<GeneralInfo, GeneralInfo>(gi2, gi);

gi.PersonList.Count = 0, How to fix it?

using System;
using System.Collections.Generic;
using AutoMapper;

public class Program
{
   public static void Main(string[] args)
    {
        Mapper.Initialize(cfg =>
        {
            cfg.AllowNullCollections = true;
            cfg.CreateMap<GeneralInfo, GeneralInfo>()
            .ForAllMembers(opts => opts.Condition((src, dest, srcMember) =>
                srcMember != null
            ));

        });
        GeneralInfo gi = new GeneralInfo();
        gi.Descr = "Test";
        gi.Dt = DateTime.Now;
        gi.Qty = 1;
        gi.PersonList = new List<Person>();
        gi.PersonList.Add(new Person { Num = 1, Name = "John", Surname = "Scott" });

        GeneralInfo gi2 = new GeneralInfo();
        gi2.Qty = 3;

        Console.WriteLine("Count antes de mapeo = " + gi.PersonList.Count);

        Mapper.Map<GeneralInfo, GeneralInfo>(gi2, gi);

        Console.WriteLine("Count despues de mapeo = " + gi.PersonList.Count);
        // Error : gi.PersonList.Count == 0 !!!! 
        //por que? si arriba esta: Condition((src, dest, srcMember) => srcMember != null ...

    }
}

class Person
{
    public int Num { get; set; }
    public string Name { get; set; }
    public string Surname { get; set; }
}

class GeneralInfo
{
    public int? Qty { get; set; }
    public DateTime? Dt { get; set; }
    public string Descr { get; set; }
    public List<Person> PersonList { get; set; }
}

https://dotnetfiddle.net/N8fyJh

+4

c # automapper mapper

Alexey Vladyshevsky Dec 15 '17 at 15:05

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2 answers

:

gi = Mapper.Map<GeneralInfo, GeneralInfo>(gi2);

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+1

lucky Dec 15 '17 at 15:41

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NSGaga · Accepted Answer · 2017-12-16T20:47:56+0000

This should work, but I'm not sure if you want the micro to control it like this:

cfg.AllowNullCollections = true;
cfg.CreateMap<GeneralInfo, GeneralInfo>()
    .ForMember(x => x.PersonList, opts => opts.PreCondition((src) => src.PersonList != null));

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:
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cfg.CreateMap<GeneralInfo, GeneralInfo>()
.ForAllMembers(opts =>
    {
        opts.PreCondition((src, context) =>
        {
            // we can do this as you have a mapping in between the same types and no special handling
            // (i.e. destination member is the same as the source property)
            var property = opts.DestinationMember as System.Reflection.PropertyInfo;
            if (property == null) throw new InvalidOperationException();
            var value = property.GetValue(src);
            return value != null;
        });
    }
);