title: Double Buffering with vsync (in sync with refresh rate of screen) - C# windows forms
body: <p>I've been trying to update the BMP of a PictureBox 60 times per second with a line pattern that changes for every update. What's happening is the image is being partially updated in between screen refreshes. So, what you see is part of one pattern and part of the next. I need to update precisely once for every screen refresh. Ideally, my goal is to update a back buffer and then copy it into the front buffer. I've heard that you can use vsync in games to lock the front buffer such that the screen is only updated right after the screen refreshes. If I could take advantage of that locking, it would allow me to precisely updated once per refresh. But I haven't been able to figure out how to do it yet. </p>
  
  <p>Any ideas?</p>
  
  <p>I did try using the DoubleBuffering = true property in windows forms. But it might not work for the PictureBox. I used CopyMemory (a native dll call) to copy the new pattern into the bitmap that is in the PictureBox.</p>
  
  <p>I also tried to use WriteableBitmap with the same technique in the last paragraph, but for some reason the back buffer is never copied to the front buffer, even though I did it the way other people suggested on stack exchange. I tried this for a couple hours or so. The image never updated on the screen with that technique.</p>