Scheduled task agents do not have access to the entire set of APIs that foreground apps do. There is a set of APIs that are off-limits, and using an API from the set either raises an
UnauthorizedAccessException at runtime or causes the app to fail certification during submission to the Windows Phone Marketplace. For the list of unsupported APIs, see Table 32.3.
One noteworthy limitation is the inability to display visual elements from a background agent. You see a workaround in the next section.
On occasion, your background ...