WPF Application unexpectedly closed

Don't create any windows before you create your application, or they won't get registered properly. They won't show up in Application.Current.Windows or Application.Current.MainWindow. Then when you create your dialog window, your application will think that it is both the MainWindow and the only window.
Example of what not to do:

public partial class App : Application, ISingleInstanceApp

{

MyWindow win = new MyWindow(); //BAD! this is called inside new App(), but before the actual App constructor.

[STAThread]

public static void Main()

{

if (SingleInstance.InitializeAsFirstInstance(Unique))

{

var application = new App();

application.InitializeComponent();

application.Run();

// Allow single instance code to perform cleanup operations

SingleInstance.Cleanup();

}

1 Reply

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Rajendra Tripathy12y ago
Don't create any windows before you create your application, or they won't get registered properly. They won't show up in Application.Current.Windows or Application.Current.MainWindow. Then when you create your dialog window, your application will think that it is both the MainWindow and the only window.
Example of what not to do:

public partial class App : Application, ISingleInstanceApp
{
MyWindow win = new MyWindow(); //BAD! this is called inside new App(), but before the actual App constructor.

[STAThread]
public static void Main()
{
if (SingleInstance.InitializeAsFirstInstance(Unique))
{
var application = new App();

application.InitializeComponent();
application.Run();

// Allow single instance code to perform cleanup operations
SingleInstance.Cleanup();
}
}