Paging with DbSet<>.Local

Question

I'm trying to page a data set in a WPF application.

My service method looks like this:

public ObservableCollection<MyModel> GetPageOfModels(int projectId, int numSkip, int numResults)
{
  this.db.Set<MyModel>()
    .Where(x => x.Project.Id == projectId)
    .OrderBy(x => x.Name)
    .Skip(numSkip)
    .Take(numResults)
    .Load();

  return this.db.Set<MyModel>().Local;
}

This works great the first time it is hit. But when I move to a different page, Load() is adding the next page to the set, rather than replacing it.

If I recreate the data context before each call to GetPageOfModels it works, but I need to keep the same data context. Is there any way to achieve this?

Answer 1

If you must keep the context then you could detach everything before getting the next page.

foreach(var entity in db.Set<MyModel>().Local.ToList())
   db.Entry(entity).State = EntityState.Detached;