Inconsistent behavior in Automapper

Question

Very strange thing happened in my project, i have a pretty simple CLR objects, First one is the Model other is ViewModel, after i compile the project i run my WebApi ASP.NET project, with the required parameters, i can see that my Model return with data.

Once i can see the Mapper did mapping ok, and the second time it's return every thing with nulls. The problem that is not happens all the time.

Very Important: Update 14.03.2013
It's stop doing it when i recycle application, but after a while it's start doing it again, i re-save the web.config file then it's ok again.

Here is my Model/ViewModel:

public class Gallery : Entity
{
    public override long Id { get; set; }
    public virtual Settings SiteOwner { get; set; }
    public virtual Category Category { get; set; }
    public virtual string PageTitle { get; set; }
    public virtual string TitleDescription { get; set; }
    public virtual string GalleryTitle { get; set; }
    public virtual IList<UIItem> GalleryItems { get; set; }
}

public class UIItem : Entity
{
    public override long Id { get; set; }
    public virtual Product Product { get; set; }
    public virtual Gallery Gallery { get; set; }
    public virtual string Name { get; set; }
    public virtual string Description { get; set; }
    public virtual string Price { get; set; }
    public virtual string ImageUrl { get; set; }
    public virtual string VideoUrl { get; set; }
    public virtual string FileUrl { get; set; }
}
public class GalleryViewModel
{
    public virtual string PageTitle { get; set; }
    public virtual string TitleDescription { get; set; }
    public virtual string GalleryTitle { get; set; }
    public virtual IList<UIItemViewModel> GalleryItems { get; set; }
}

public class UIItemViewModel
{
    public virtual long Id { get; set; }
    public virtual string Name { get; set; }
    public virtual string Description { get; set; }
    public virtual string Price { get; set; }
    public virtual string ImageUrl { get; set; }
    public virtual string VideoUrl { get; set; }
    public virtual string FileUrl { get; set; }
}

Here is the way i use it

// my apicontroller

// FindGalleryByAppIdAndCategoryId returns => Gallery 
var source = _galleryRepository.FindGalleryByAppIdAndCategoryId(appId, catId);
return Mapper.DynamicMap<GalleryViewModel>(source);

can you please mention the return type of FindGalleryByAppIdAndCategoryId OR what exact type is source — Parv Sharma
– Parv Sharma, Commented Mar 14, 2013 at 8:29
please check that when you are getting null values in the galleryViewModel the source that you are passing in isn't null — Parv Sharma
– Parv Sharma, Commented Mar 14, 2013 at 8:37
Yes i have checked it and the result is always good that contains objects — hackp0int
– hackp0int, Commented Mar 14, 2013 at 8:44

Igor Lozovsky · Accepted Answer · 2013-03-15 13:38:22Z

3

Why did you marked your non-navigational properties with virtual keyword? Only properties, which involved in relations one-to-one, one-to-many, many-to-many and complex types can be marked with virtual keyword to apply lazy loading.

2.

Mapper.CreateMap<UIItem,UIItemViewModel>();
...
UIItemViewModel result = Mapper.Map<UIItem,UIItemViewModel>(your UIItem);

If you need special mapping logic, you can do like this:

Mapper.CreateMap<UIItem,UIItemViewModel>().ConvertUsing(new ModelToViewModelConverter());
...
UIItemViewModel result = Mapper.Map<UIItem,UIItemViewModel>(your UIItem);
...

Converter will be look like this:

public class ModelToViewModelConverter : ITypeConverter<UIItem,UIItemViewModel>
    {
        public UIItemViewModel Convert(ResolutionContext context)
        {
            UIItem item = (UIItem)context.SourceValue;
            // Perform your convertion logic 
        }
    }

In the same way you can map all of your entities even collection to collection.

answered Mar 15, 2013 at 13:38

Igor Lozovsky

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1 Comment

Patrick Magee Over a year ago

Indeed what I was thinking, im not sure why he's relying on the DynamicMap if its not actually necessary. I would only use Dynamic in dire situations

Dima · Accepted Answer · 2013-03-14 09:04:10Z

2

+50

Most likely this happens in cases, when Gallery and UIItem have cross references:

public class Gallery : Entity
{
    public virtual IList<UIItem> GalleryItems { get; set; }
}

public class UIItem : Entity
{
    public virtual Gallery Gallery { get; set; }
}

Can you please test this case in your code?

answered Mar 14, 2013 at 9:04

Dima

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2 Comments

hackp0int Over a year ago

Yes i will test it but one problem i do not map it to the DomainModel to DomainModel i map to ViewModel

Dima Over a year ago

Unfortunately, I cannot reproduce erroneous behaviour

Patrick Magee · Accepted Answer · 2013-03-14 16:26:24Z

1

Can you try using

Mapper.Map<Source,Destination>(source);

or

Mapper.Map(source);

and ensure you have declared a

CreateMap<Source, Destination>();

I don't see your reason for using Dynamic Map when you can declare a CreateMap of the two types. You shouldn't experience this behaviour doing it this way.

answered Mar 14, 2013 at 16:26

Patrick Magee

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