How to open window directly after main application window

Question

My app's main UI is in MainWindow.xaml.

Firstly - what is causing this to be the window the application opens on startup. It does not appear to be defined as a "starup object" and there does not appear to be any code that specifically launches this window.

I can make my login window appear when the app starts by in the loaded event of MainWindow.xaml defining a new "login.xaml" and telling it to show as a dialog. However, if I do this then MainWindow does not appear until Login has been closed.

What I want to achieve is when my app starts, the MainWindow appears and then on top of that the Login window is displayed modally.

How can this be done?

Answer 1

1. The startup of the MainWindow is defined in App.xaml by default when creating a project in VS:

   <Application ...
                StartupUri="MainWindow.xaml">
       <Application.Resources>
   
       </Application.Resources>
   </Application>
   

2. Creating the dialogue in the Loaded event should work, just don't do it in the constructor where it is not yet loaded.

   Loaded="Window_Loaded"
   

   private void Window_Loaded(object sender, RoutedEventArgs e)
   {
       new LoginDialogue().ShowDialog();
   }
   

Answer 2

One way could be to add a Loaded event handler to your main window and in that display the login window:

this.Loaded += LoadedEventHander;


void LoadedEventHander(object sender, RoutedEventArgs e)
{
    // Show Login.xaml here.
}

Answer 3

1. In app.xaml the following line defines the startup window, you can change it if you want

   StartupUri="MainWindowView.xaml"
   

2. If you are following MVVM you can bind a command to the windows loaded event using System.Windows.Interactivity (otherwise simply create an event handler as the others have suggested)

   <i:Interaction.Triggers>
       <i:EventTrigger EventName="Loaded">
           <i:InvokeCommandAction Command="{Binding MyICommand}"/>
       </i:EventTrigger>
   </i:Interaction.Triggers>