System.TypeInitializationException when changing MainWindow startupUri WPF

Question

I am trying to change the MainWindow location in a WPF application from the default startup URI: MainWindow.xaml to Views\MainWindow.xaml. where Views is a folder created inside the project folder.

Uri: this.StartupUri = new System.Uri(@"Views\MainWindow.xaml", System.UriKind.Relative);

I changed the uri and then the application breaks with the following error:

 An unhandled exception of type 'System.TypeInitializationException'occurred in PresentationFramework.dll


Additional information: The type initializer for 'System.Windows.Application' threw an exception.

I placed breakpoints and try-catch blocks in the Main method,the InitializeComponent method and the MainWindow constructor to no avail.It crashes and i can't catch the exception.

Main:

public static void Main() {
            try
            {
                wpfTest.App app = new wpfTest.App();
                app.InitializeComponent();
                app.Run();
            }catch(Exception ex)
            {
                Console.WriteLine(ex.InnerException.Message);
            }
        }

Does the startupUri have to be changed somewhere else too?It has only one reference :the one in the InitializeComponent method.

score 1 · Accepted Answer · answered Sep 18 '17 at 07:52

To move the MainWindow to a Views folder (namespace), you have to follow this steps

Change the class name in MainWindow.xaml

<Window x:Class="WpfApp1.Views.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:WpfApp1"
        mc:Ignorable="d"
        Title="MainWindow" Height="350" Width="525">
    <Grid>

    </Grid>
</Window>

Modify the namespace in MainWindow.xaml.cs

namespace WpfApp1.Views
{
    /// <summary>
    /// Interaktionslogik für MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }
}

Modify the App.xaml

<Application x:Class="WpfApp1.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:local="clr-namespace:WpfApp1"
             StartupUri="Views/MainWindow.xaml">
    <Application.Resources>

    </Application.Resources>
</Application>

Move MainWindow.xaml to the Views folder

And thats it.

It does not matter which one you do first/last, but you have to do all of them.

Thank you very much sir ! Indeed it worked. I knew i was missing something somewhere and the startup uri in the app.cs change was not enough. — , Sep 18 '17 at 08:05

System.TypeInitializationException when changing MainWindow startupUri WPF

1 Answers1