odata deep-level expand not working

Question

I am trying to perform a nested expand on one of my odata queries (3 levels) and am unable to get the expanded object to be returned.

Here are my classes:

public class Project
{
    public int ProjectId { get; set; }
    public Manager Manager { get; set; }
    public IEnumerable<ProjectResource> ProjectResources { get; set; }
}

public class ProjectResource
{
    public int ProjectResourceId { get; set; }
    public Employee Employee { get; set; }
    public Project Project { get; set; }
    public IEnumerable<Forecast> Forecasts { get; set; }
}

public class Employee
{
    public int EmployeeId { get; set; }
    public string Name { get; set; }
    public Manager Manager { get; set; }
    public IEnumerable<ProjectResource> ProjectResources { get; set; }
}

public class Manager
{
    public int ManagerId { get; set; }
    public string Name { get; set; }
}

public class Forecast
{
    public int ForecastId { get; set; }
    public ProjectResource ProjectResource { get; set; }
}

The following odata query works, and a list of Projects and their Managers is returned:

/Projects?$expand=Manager

I then tried this query, and it worked:

/Forecasts?$expand=ProjectResource($expand=Project)

Adding another level of expand:

/Forecasts?$expand=ProjectResource($expand=Project($expand=Manager))

And I get an error saying that I can only expand 2 levels. So I add this to my query and retry:

[EnableQuery(MaxExpansionDepth=0)]

I don't get the error anymore, but the Manager for each Project is not included. Any idea on what I'm missing?

Answer 1

I was struggling with the same problem. Turns out that adding all of the entity sets during the configuration allows the $expand to work properly after 2 levels. Add all your entity sets like this:

builder.EntitySet<Item>("Items");
builder.EntitySet<Product>("Products");
builder.EntitySet<Model>("Models");
builder.EntitySet<Type>("Types");

I also set [EnableQuery(MaxExpansionDepth=0)] as an attribute on the controller.

Answer 2

You need to add all of the entity sets during the configuration allows the $expand to work properly after 2 levels.

The SO Question that claims that this issue is related to complex type is NOT valid.

Hope it helps save someone his time, just wasted 2 days because of this!