How to write a delay function in VS2010 C++

Why are you using a timer? You should rather just invalidate[^] your display whenever the data changes.

A third solution is to combine the idea from both solutions...

Essentially each time a change is made, a timer is used to delay the update. If another change occurs before the timer has elapsed, then their update will be combined.

But I would go with relatively small delay like 500 ms. But it depends on the application.

My solution would be appropriate when it take some time to process changes (say a few seconds) but you want to combine changes that occurs in a batch (for example, keyboard auto-repeat).