Set focus to datagrid from treeview

Question

I'm attempting to set the focus to a datagrid after a selection has been made in a treeview. I'm capturing the correct value in the treeview, and making a decision based on that value, so things are working to that point. Now I simply want to set focus to a datagrid, any row, any column. In the past I've had to use a delegate, but I'm unclear if this is true in WPF. Seems simple, but so far the solution is elusive.