I know this was already mentioned in the IRC channel, but I'm answering here so others are aware, and also to address your further question that I'm not sure anyone answered.
New in 1.4 If you set the value of the field to "_item", then your formatter will be called with the entire item from the store - instead of just one field value
This makes it possible to do what you want using a formatter as well.
http://www.dojotoolkit.org/reference-guide/dojox/grid/DataGrid.html#usage
In the simplest case, without setting the grid's formatterScope, the grid's store can be accessed from within formatters via this.grid.store
, e.g.:
function fmtItem(value) {
var store = this.grid.store;
return store.getValue(value, 'id') + ': ' + store.getValue(value, 'name');
}
Here's a really simple example of the above formatter in action:
http://jsbin.com/upico4/edit
There's also an example of this in one of the test pages, which creates an object to hold and scope the formatters:
http://archive.dojotoolkit.org/nightly/dojotoolkit/dojox/grid/tests/test_grid_formatters.html