Notes

Now we hide the CategoryID and Picture columns by using the gridLens property. Only columns we want to display are listed here.

$lens->gridLens = "CategoryName;Description";

You can also hide the columns dynamicly by clicking on the [pict here] button and selecting the columns you want to see in the grid [picture here]

For best performance, instead of hiding columns, only retrieve the columns you need. In SQL, use:
SELECT categoryname, description FROM categories