Disconnect your data context beforehand, then reattach it afterwards. I don't know what you have attached your DataContext to so here's an example using something called _myUserControl as the target of the DataContext, which we are storing in DataContextSource (this is an example only).
private void ConnectData()
{
_myUserControl.DataContext = null;
DataGrid.ItemsSource = Data;
_myUserControl.DataContext = DataContextSource;
}