DataGrid Update Instantly

Question

I have been trying to update the DataGrid instantly but the DataGrid is only updating after completing the Button_Click function that I called, Here is a sample of my code, rows variable is binded to DataGrid

public ListCollectionView rows;
private void Button_Click(object sender, RoutedEventArgs e)
{
     for(int i=0;i<5;i++)
     {
        function1();
        //Adding values to rows variable
        //Update the DataGrid at this instant with current data available
        //DataGrid.Refresh();
        System.Threading.Thread.Sleep(5000);
     }
}