Use the 'presence' property. If your row is a static row (ie you see it in design time), then simply reference the name: myRow.presence="hidden" or myRow.presence="visible".
However, if it's a dynamic row (ie you add them at run time), then you have to reference the name of the row along with its index: myRow.all.item(3).presence="hidden". The index of a row is zero-based, that means the first row is 0 and in my example row 3 is the 4th from the top.
Kyle