Windows Phone C ++

Question

I'm writing simple application for WP 8.1 using C++/cx. My problem starts when I'm trying to do something in some event. For example if I create simple button event "tapped" and I want to do something inside for example change the color of the button background, it doesn't execute in the correct time. I mean that for the code below it will first execute Somefunction() and then change the color of the button.Same happens for example when I try to show message box using message dialog and ShowAsync function.

but->Background = ref new SolidColorBrush(Windows::UI::Colors::Red);
Somefunciton();

Answer 1

You have the background change and the function call in the same function and that function gets executed on one thread blocking it. This thread happens to be the UI thread which gets blocked for the time of your function execution. So you set the button background but the actual change will be applied only when the UI thread could run the render function and it will be able to do it only after your function call ends.

So in terms of program execution the button background gets updated before the call to Somefunciton(); . But visual changes are delayed until after the function call is completed so you might think that Somefunciton(); gets called before the background is set which is not the case.