Programming WPF, 2nd Edition

ProgressBar

The ProgressBar control indicates how much of a long-running process the application has completed. It provides the user with an indication that work is progressing, and a rough idea of how long the user will need to wait for work to complete. As Figure 5-8 shows, it is approximately rectangular, and the nearer to completion the task is, the more of the rectangle is filled in by a color bar. If an operation is likely to take much more than a second, you should consider showing a ProgressBar to let users know how long they are likely to wait.

Figure 5-8. ProgressBar control

ProgressBar derives from RangeBase, the same base class as the scroll bar and slider controls discussed in the preceding section. From a developer perspective, it is very similar to these other range controls, the main difference being that it does not respond to user input— sadly, users cannot drag the progress bar indicator to the right in order to make things run faster. The progress indicator's size is based on the Value property, so it is your application's responsibility to update this as work progresses.