Vfrdtyky

I want to reuse the intialized mappings of the c# Automapper (using version 6.2.2) by looping through all mapped properties.

Let's suppose I have the following:

public class Person

{

    public int Id { get; set; }

    public string FirstName { get; set; }

    public string LastName { get; set; }

}



public class PersonDto

{

    public int Id { get; set; }

    public string FullName { get; set; }

}



AutoMapper.Mapper.Initialize(cfg =>

{

    cfg.CreateMap<Person, PersonDto>()

        .ForMember(dest => dest.FullName, 

                    opt => opt.MapFrom(src => src.FirstName + " " + src.LastName));

};

The loop for Id behaves as expected:

var map = AutoMapper.Mapper.Configuration.FindTypeMapFor<Person, PersonDto>();

foreach (var propertyMap in map.GetPropertyMaps())

{

    var destProp = propertyMap.DestinationProperty.Name; // = "Id"

    var sourceMember = propertyMap.SourceMember.Name; // = "Id"

    var sourceMembers = propertyMap.SourceMembers; // Count = 1

}

But when I loop through the FullName property mapping, I want to achieve that the propertyMap.SourceMembers results in the two SourceMembers FirstName and LastName:

var map = AutoMapper.Mapper.Configuration.FindTypeMapFor<Person, PersonDto>();

foreach (var propertyMap in map.GetPropertyMaps())

{

    var destProp = propertyMap.DestinationProperty.Name; // = "FullName"

    var sourceMember = propertyMap.SourceMember.Name; // = "LastName" (I don't care)

    var sourceMembers = propertyMap.SourceMembers; // Count = 0 (want to achieve 2 for FirstName and LastName)

}

My goal is to create an automated similar mapping for an orderBy functionality based on the initialized automapper mappings. So I need to know (a) the order and (b) the sourceMembers. In the above case I want get the mapping for FullName from its source members FirstName and LastName (in this order).

Is it somehow possible to correctly register multiple source members so that propertyMap.SourceMembers yields all mapped source members? If yes, what should the map initialization look like?

PS: I don't want to write the orderBy mappings by hand, since I already have mappings thanks to automapper.

Thanks to Lucian Bargaoanu, I developed the following dirty workaround.

Please note that this is the first time that I get in touch with interpreting expressions, so bear with me the quality of my solution:

var map = AutoMapper.Mapper.Configuration.FindTypeMapFor<Person, PersonDto>();

foreach (var propertyMap in map.PropertyMaps)

{

    var destProp = propertyMap.DestinationMember.Name; // = "FullName"

    var sourceMember = propertyMap.SourceMember?.Name; // = "LastName" (I don't care)

    var sourceMembers = propertyMap.SourceMembers.ToList();

    if (sourceMembers.Count() == 0)

    {

        ResolveSourceMembersInOrder(sourceMembers,

            propertyMap.CustomMapExpression.Body as BinaryExpression);

    }



    // sourceMembers now yield the two desired sourceMembers "FirstName" and "LastName"

}



public static void ResolveSourceMembersInOrder(List<MemberInfo> memberInfos, BinaryExpression expression)

{

    if (memberInfos == null)

    {

        memberInfos = new List<MemberInfo>();

    }



    if (expression == null)

    {

        return;

    }



    var left = expression.Left;

    if (left.NodeType == ExpressionType.MemberAccess)

    {

        memberInfos.Add(MemberVisitor.GetMemberPath(left).FirstOrDefault());

    }

    else

    {

        ResolveSourceMembersInOrder(memberInfos, left as BinaryExpression);

    }



    var right = expression.Right;

    if (right.NodeType == ExpressionType.MemberAccess)

    {

        memberInfos.Add(MemberVisitor.GetMemberPath(right).FirstOrDefault());

    }

    else

    {

        ResolveSourceMembersInOrder(memberInfos, right as BinaryExpression);

    }

}