SQL 2012 :: Entity Framework Returning Cached Data

I have a datagridview bound to a table that is part of an Entity Framework model. A user can edit data in the datagridview and save the changes back to SQL. But, there is a stored procedure that can also change the data, in SQL, not in the datagridview. When I try to "refresh" the datagridview the linq query always returned the older cached data. Here's the code that I have tried using to force EF to pull retrieve new data:

// now refresh the maintenance datagridview data source
using (var context = new spdwEntities())
{
var maintData =
from o in spdwContext.MR_EquipmentCheck
where o.ProdDate == editDate
orderby o.Caster, o.Strand
select o;
mnt_DGV.DataSource = maintData;
}

When I debug, I can see that the SQL table has the updated data in it, but when this snippet of code runs, maintData has the old data in it.