The underlying connection was closed error while using .Include on EF objects - wcf

Question

Following line of code gives me an error saying "The underlying connection was closed".
return this.repository.GetQuery<Countries>().Include(g => g.Cities).AsEnumerable().ToList();
But if I remove .Include(g => g.cities) it works fine.
this code is written in one of the operation in my WCF service, and I try to test it using WCF test client. I tried by calling this operation from MVC application also, and the same issue was occurring there too.
Also, i am using generic repository with entity framework
Repository code (only few important extract)
Constructor:
public GenericRepository(DbContext objectContext)
{
if (objectContext == null)
throw new ArgumentNullException("objectContext");
this._dbContext = objectContext;
this._dbContext.Configuration.LazyLoadingEnabled = false;
this._dbContext.Configuration.ProxyCreationEnabled = false;
}
GetQuery method:
public IQueryable<TEntity> GetQuery<TEntity>() where TEntity : class
{
var entityName = GetEntityName<TEntity>();
return ((IObjectContextAdapter)DbContext).ObjectContext.CreateQuery<TEntity>(entityName);
}
Attempt#1
Created following overloads in repository code:
public IQueryable<TEntity> GetQuery<TEntity>(params string[] includes) where TEntity : class
{
var entityName = GetEntityName<TEntity>();
IQueryable<TEntity> query = ((IObjectContextAdapter)DbContext).ObjectContext.CreateQuery<TEntity>(entityName);
foreach(string include in includes)
{
query = query.Include(include);
}
return query;
}
public IQueryable<TEntity> GetQuery<TEntity>(Expression<Func<TEntity, bool>> predicate, params string[] includes) where TEntity : class
{
return GetQuery<TEntity>(includes).Where(predicate);
}
WCF is now trying to execute following line of code:
return this.repository.GetQuery<Countries>("Cities").AsEnumerable().ToList()
But it still gives the same error of "The underlying connection was closed". I tested it in WCF test client. However, when I debug the repository code it shows the navigation object getting included in result, but the issue seems occurring while trying to pass the output to client (WCF test client, or any other client)

Answer 1

After looking at the code you've now posted, I can conclude that, indeed, your DbContext is being closed at the end of the GetQuery method, and is thus failing when you try to use include. What you might want to do to solve it is to have an optional params variable for the GetQuery method that will take in some properties to be included, and just do the include right in the GetQuery method itself.