Working With The UI Thread In iOS Using Xamarin - Part 2

Application user interfaces are always single-threaded, even in multi-threaded devices – there’s only one representation of the screen and any changes to what is displayed need to be coordinated through a single ‘access point’. This prevents multiple threads from trying to update the same pixel at the same time (for example)!

Your code should only make changes to user interface controls from the main (or UI) thread. Any UI updates that occur on a different thread (such as a callback or background thread) may not get rendered to the screen, or could even cause a crash.

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