How to refresh datagrid!

I currently have an app that has around 20 tabs that share one datagrid. These tabs are displaying data from a sql database. What i am having trouble with is getting the datagrid to refresh. Users can add new items via a popup window, when that windows closes i want the grid to refresh. I aslo want to be able to have the grid update automatically every hour so that it is always displaying updated info. How should i go about making this happen? I have been looking into observable collections, but Im not sure if that is best for what I am trying to do. Any help is appreciated. thanks