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 expectatio

Answer 1

Here's a simplified version of what I do (error handling removed). If the initialization takes a while, you may want to display a splash screen while you're doing your thing.

App.xaml:

<Application x:Class="MyProgram.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             Startup="App_StartUp" >
</Application>

App.xaml.cs:

namespace MyProgram
{
    public partial class App : Application
    {
        private void App_StartUp(object sender, StartupEventArgs e)
        {
            // Create the model and MainWindow
            MyModel model = CreateModel();
            MainViewModel viewModel = new MainViewModel(model);
            MainWindow = new MainWindow(viewModel); // Sets the DataContext

            // Do things, like initialize your model
            model.Initialize();

            // Now show your window
            MainWindow.Show();
        }
    }
}

Answer 2

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.