public void Detach(string logicalName, Guid?id)
{
if (this.context != null)
{
var candidates = (from c in this.context.GetAttachedEntities() where c.LogicalName == logicalName select c);
if (id != null)
{
candidates = (from c in candidates where c.Id == id.Value select c);
}
foreach (var r in candidates.ToArray())
{
context.Detach(r);
}
}
}