private void BindingContextPageChanged(object sender, BindingContextChangeRequestMessage messageArgs)
{
if (MainPage != null)
{
// Same as with the page; the app state is about to change
NavAndMenuBar.OnAppStateChanged(MainPage, messageArgs.PreventNavStackPush);
MainPage.BindingContext = messageArgs.Payload;
}
}
private void MainPageChanged(object sender, MainPageChangeRequestMessage messageArgs)
{
// Try to avoid changing the page is possible
if (
messageArgs?.Payload == null
||
MainPage == null
||
(
_lastMainPage != null
&&
_lastMainPage.GetType() == messageArgs.Payload.GetType()
)
)
{
return;
}
// Notify the nav bar directly before the change so it can preserve the existing main page binding context app state
NavAndMenuBar.OnAppStateChanged(MainPage, messageArgs.PreventNavStackPush);
MainPage = messageArgs.Payload;
// IMPORTANT -- The assignment above often fails to cause Page.Disappearing for some reason
if (_lastMainPage != null)
{
if (_lastMainPage is IDisposable lastMainPageAsDisposablew)
{
lastMainPageAsDisposablew.Dispose();
}
_lastMainPage = null;
}
_lastMainPage = MainPage;
}