Question

The loaded event on my MainPage is getting called twice on application startup.

The constructor of the page is only getting once, and I am pretty sure that I am only assigning the event handler once also. What is going on?

Answer 1

Took me a while to work out what was going on, but it turns out the loaded event shouldn’t be used on pages for initialization tasks, as it is not guaranteed to be called only once.

OnNavigatedTo should always be used instead. See the MSDN article below.

Typically, you use the OnNavigatedTo method instead of creating an
event handler for the Loaded event. The OnNavigatedTo method is
preferable because it is only called once for each time the page
becomes active. The Silverlight framework raises the Loaded event each
time the element is added to the visual tree, which potentially can
happen more than once when activating a page.