Question

I have a WPF desktop application where I want to check if I can connect to my database with EF before launching the main window. So I try to connect to database and if exception occurs, I simply show a window where I ask the user to enter correct database connection string.

After user enters the connection string, I retry connecting to database and if it connects I want to launch my main window and let the application start.

EDIT: I changed my code a liitle bit, but still doesn’t work. I think it is about closing one window and then trying to show another window in Application class. It works if ServerConfigurationWin is not shown.

However what happens is, after I display the database configuration window to user, the application calls the StartupUri window’s constructor declared in App.xaml file but nothing shows on screen.

Thanks.

Here is my App code:

public partial class App : Application
{
    protected override void OnStartup(StartupEventArgs e)
    {
        base.OnStartup(e);

        bool success = false;
        while (!success)
        {
            try
            {
                DemirbasContext context = new DemirbasContext();
                DbInitializer initializer = new DbInitializer();
                Database.SetInitializer<DemirbasContext>(initializer);
                context.Database.Initialize(false);
                success = true;
            }
            catch (ProviderIncompatibleException)
            {
                ServerConfigurationWin configurationWin = new ServerConfigurationWin();
                if (!configurationWin.ShowThemAll())
                {
                    // ShowThemAll() returns that operation is canceled.
                    App.Current.Shutdown();
                    return;
                }
                success = false;
            }
        }
    }

    public App()
    {

    }

    void App_DispatcherUnhandledException(object sender, DispatcherUnhandledExceptionEventArgs e)
    {
        // Process unhandled exception do stuff below
        Console.WriteLine("***Message***");
        Console.WriteLine(e.Exception.Message);
        Console.WriteLine("***Stack Trace***");
        Console.WriteLine(e.Exception.StackTrace);
        Console.WriteLine("***Target Site***");
        Console.WriteLine(e.Exception.TargetSite);
        // Prevent default unhandled exception processing
        e.Handled = true;
    }
}

App.xaml:

<Application x:Class="Demirbas.App"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         DispatcherUnhandledException="App_DispatcherUnhandledException"
         StartupUri="Enterance.xaml">
<Application.Resources>
    <Style TargetType="Button">
        <Setter Property="Height" Value="25" />
        <Setter Property="Width" Value="75" />
        <Setter Property="MinWidth" Value="25" />
        <Setter Property="Margin" Value="5,0" />
        <Setter Property="Padding" Value="0" />
    </Style>
    <Style TargetType="Label">
        <Setter Property="Margin" Value="5,0" />
    </Style>

</Application.Resources>

Answer 1

It seems you cannot show a second window from your Application class. So I had to shutdown the application and start again.