The following json and jqgrid options give me no data in my grid.
var grid = jQuery("#grid")[0];
grid.addJSONData({ // the json
    total: 1,
    page: 1,
    records: 10,
    items: [
        { ProductID: '1', Name: 'Coke' },
        { ProductID: '2', Name: 'Pepsi' },
        { ProductID: '3', Name: 'L&P' },
        { ProductID: '4', Name: 'A&B' },
        { ProductID: '5', Name: 'All Star' },
        { ProductID: '6', Name: 'Wai' },
        { ProductID: '7', Name: 'cd' },
        { ProductID: '8', Name: 'LV' },
        { ProductID: '9', Name: 'DD' },
        { ProductID: '10', Name: 'aW' }
    ]
});
// jqGrid options
{
    ...
    colNames: ['ProductID', 'Name'],
    colModel: [{ name: 'ProductID', Label: 'Id' },
               { name: 'Name', Label: 'Name'}],
    jsonReader: {
        root: 'items',
        cell: ''
    },
   ...
}