Listen to the 'onCellEdit' event, get the 'checkbox' editor and then you can bind the 'change' event on it. Please look at the code below:
$('#dg').datagrid({
data: data,
onCellEdit: function(index,field,value){
if (field == 'status'){
var ck = $(this).datagrid('getEditor', {index:index,field:field});
$(ck.target).bind('change', function(e){
//...
})
}
}
}).datagrid('enableCellEditing').datagrid('gotoCell', {
index: 0,
field: 'productid'
});