Using background threads for long processes in MFC: Foreground Thread 1

15 Apr 2003 11:41 mfc

Initially, we’ll run this as a foreground task. This will ensure that the code compiles and works before we get too complicated. Also, it’ll show why we want this task to run as a background thread.

To do this, add these files to the MFC dialog project, and add a button to the dialog. The code for the button should look something like this:

void CBgthreadDlg::OnForeground()
    Task task(NULL);

This runs our task on the foreground thread. This is the simplest solution. It demonstrates why we want our task to run in the background:

  • There’s no feedback to the user that the application is busy.
  • Try to move the dialog. You can’t. Or, more accurately, it doesn’t move until the task is finished, and control is returned to the main message loop.
  • The window doesn’t repaint until the task is finished.