c# - Understand WPF Window Events

Question

I see Windows have a Loaded event, but not a Loading event (as there is Closing and Closed events).

My expectation was that the Loaded event would occur before the window is actually displayed. However, looking at the Window Lifetime Events, it shows that the Loaded event occurs after Activated event.

I put some initialization code in the Loaded event and there is a delay after the window is displayed and before my content appears. So what is the best event handler to use for window initialization that should occur before the window is displayed?

Answer 1

You can override OnStartup() in App.xaml.cs, and do stuff before calling base.OnStartup(e);. I just checked and this is fired before the window's constructor.

Alternatively, set the window's visibility to Hidden in its xaml file, do your initialization in the constructor and then set the visibility to Visible once done. This won't remove the delay, but the delay is only caused by whatever your initialization code is doing, so it's unavoidable unless you go asynchronous.