Erase Contents of Grid without running XML request

How can I erase all the rows in a grid without making a roundtrip to the server (I am using XML dataset) to retrieve an empty dataset?

Maybe this:

function clearGrid(){
        obj.setRowProperty("values", []);
        obj.refresh();
    }

with the release 2 beta 2, it wasn't working.

This works for me :

function clearGrid(grid){
grid.setRowCount(0);
grid.refresh();
}

You can also clear the entire grid, headers/footers included (it will keep it's size and position etc), using obj.clear(). But if you want to keep the headers/footers then use the above example.