LINQ-TO-SQL Refresh() not updating object's associations after some external database update such as ExecuteCommand()

Lets say I have an entity called Department that I retrieved from MyDataContext. Department has an association called Employees.

I want to add a bunch of new Employees to a Department. Instead of using LINQ, which would result in multiple queries, I do one bulk insert with:

MyDataContext.ExcecuteCommand(
"Insert INTO Employee (DeptID, etc…), (DeptID, etc…), (DeptID, etc…)"
);

Now my Department object doesn’t know anything about those changes, specifically the Employees property, because Department.Employees.Count() returns 0

I've tried both of the following t开发者_开发问答o do a Refresh to update the Department and it's related Employees:

MyDataContext.Refresh(RefreshMode.OverwriteCurrentValues, Department);
MyDataContext.Refresh(RefreshMode.OverwriteCurrentValues, Department.Employees);

But still Department.Employees.Count() returns 0

I know the data was actually added correctly, because if I create a new DataContext and get the Department entity, Department.Employees.Count() = 3

How can I update MyDataContext, or my existing Department entity without using a new DataContext?

(I use one DataContext throughout the entire request, and perform several different data manipulations with it, so it would be difficult to try to introduce another DataContext)

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Unfortunately, according to this post, Refresh() will not reload associations. The suggested workaround is:

Department.Employees.Clear();
Department.Employees.AddRange(MyContext.Employees.Where(x=>x.DeptID=Department.DeptID))