Question

I am trying to create a generic typed class, but am running into a problem. Here is my basic class definition:

public class QueueObject<T> where T : System.ServiceModel.DomainServices.Client.Entity
{
    public string LoadingMessage { get; set; }
    public System.ServiceModel.DomainServices.Client.EntityQuery<T> Query { get; set; }
}

I am trying to add instances of this class to a queue

private Queue<QueueObject<Entity>> _queue;
this._queue.Enqueue(new QueueObject<MyEntity> {Query = MyContext.GetMyEntitiesQuery(), LoadingMessage = "Loading some stuff"});

This doesn’t work. I get an error saying that QueueObject cannont be converted to QueueObject. I don’t understand because MyEntity inherits from Entity. Am I doing something wrong?

Here is the same code in VB if it helps:

Public Class QueueObject(Of T As System.ServiceModel.DomainServices.Client.Entity)
    Public Property LoadingMessage As String
    Public Property Query As System.ServiceModel.DomainServices.Client.EntityQuery(Of T)
End Class

Private _queue As Queue(QueueObject(Of Entity))
Me._queue.Enqueue(New QueueObject(Of MyEntity) With {.Query = MyContext.GetMyEntitiesQuery(), .LoadingMessage = "Loading some stuff..."})

Answer 1

Still not sure about the reason for the original error, but a possible solution was to make each entity implement an interface. Then make the QueueObject be of this interface type.

I ended up going another route so this ended up being irrelevant.