Error when casting item to Complextype with Glass

Question

Im having a problem with Glass Mapper, mapping/casting an item to a custom model.

The Model with the complextype property (snippet):

[SitecoreType(TemplateId = Templates.IDString, AutoMap = true)]
public class EmployeeModel
{
    ///other propertes hidden 

    [SitecoreChildren(IsLazy = true)]
    [SitecoreField(FieldId = Templates.Items.Office.Fields.BusinessOfficeString)]
    public virtual ItemViewModel Office { get; set; }
}

The ItemViewModel:

 [SitecoreType(AutoMap =true)]
 public class ItemViewModel
 {
    public virtual ID Id { get; set; }

    public virtual string Template { get; set; }

    public virtual string Name { get; set; }

    public virtual string Url { get; set; }

    public virtual Dictionary<string, IFeatureModel> Features { get; set; }
}

To create this EmployeeModel im casting an Sitecore Item to this model:

var featureModel = _sitecoreService.Cast<EmployeeModel>(item);

But this call is throwing an error:

The type Foundation.Macaw.Modeling.Models.ViewModels.ItemViewModel does not contain any generic arguments

I think this is caused by the [SitecoreChildren(IsLazy = true)] because when i remove this line it works. However without that line an stackoverflow can be caused since the OfficeModel has a reference to Employee...

When casting directly to an ItemViewModel the same item works like a charm:

    var featureModel = _sitecoreService.Cast<EmployeeModel>(item);

Any one knows what could solve my problem?

FYI: im using Sitecore 9 Update 1 and glassmapper 4.5.04

Tnx!

Answer 1

When you use [SitecoreChildren] Glass expects the property to be an IEnumerable<T> or IList<T>. You also should not use two different Glass attributes on the same property. You can map a property from a field or from child items, but not both.

Update: I just added this other question and answer that shows the different attributes and their uses, which may be helpful for you.