> In the case of the former do I use much more memory or slow down the > execution of my program more than in the case of the latter? >
In part of your question you call the control a graph, and in other parts a chart. The answer depends a bit on which you are showing and hiding. Graphs only show the most recent data written to them, charts retain and show history. Neither the graph or chart will have much overhead receiving data while hidden. On the otherhand, it isn't zero either since they will at least be doing a data copy so they can draw with correct data when shown. It will be easiest to send the data all the time since otherwise, you will need to send fresh data when showing the graph. If dealing charts, not only will you need to update the current data, but the history will be old. You will need to clear or write the history. If it doesn't cause a problem, write to them always, but if you can measure a problem or have spare time on your hands, add code to make the update conditional and deal with the data when being shown. Greg McKaskle
