Error Loading related entities on demand (entityAspect.loadNavigationProperty())

Question

I am doing a application using durandaljs and breezejs. I am trying to get the value of a Navigation Properties. My problem is that when I tryied to call this method in breeze:

user.entityAspect.loadNavigationProperty("userType");

I get the error ""The 'propertyOrExpr' parameter must be a 'string'"". This error is throw for the follow section of code:

var q = new EntityQuery(navProperty.entityType.defaultResourceName);
var pred = buildNavigationPredicate(entity, navProperty);
q = q.where(pred);

The problem is that 'pred' is empty, because 'buildNavigationPredicate' return null. Getting into the 'buildNavigationPredicate':

if (navigationProperty.foreignKeyNames.length === 0) return null;

The problem is that the 'foreignKeyNames' array is empty, all the rest field in the 'navigationProperty' are filled, but I don't know why, but my server doesn't send this information. (Also the foreignKeyNamesServer is empty).

Do somebody have the same problem? can be it a bug of breeze?

Thanks.

jvrdelafuente jvrdelafuente · Accepted Answer · 2013-03-02T10:08:50

I found the solution yesterday and I din't have time to refresh this. The problem was in the definition of my user class. I am using Web API and EF Code first. My old user class was:

    public class User
{
    public Guid Id { get; set;}
    public string UserName { get; set; }
    public string Password { get; set; }
    public bool Active { get; set; }

    public virtual UserType UserType { get; set;}
}

To do work the user.loadNavigationProperty('userType'), I had to change the old user class in this:

    public class User
{
    public Guid Id { get; set;}
    public string UserName { get; set; }
    public string Password { get; set; }
    public bool Active { get; set; }

    public Guid UserType_Id { get; set; }

    [ForeignKey("UserType_Id")]
    public virtual UserType UserType { get; set;}
}

And doing that, I solved the problem. However, I can implement this solution for many to many relations. Doing a little of research, I have discovered, that Many to Many relations are not supported currently for breeze. So the only thing that I can do is implement a middle entity in many to many relation.

Very thanks Ward for your time. If there are any other way to solve that problem, I would be very pleased to listen. Thanks.

Error Loading related entities on demand (entityAspect.loadNavigationProperty())

2 Answers