How to make a WPF window be on top of all other windows of my app (not system wide)?

Solution 1:

You need to set the owner property of the window.

You can show a window via showdialog in order to block your main window, or you can show it normal and have it ontop of the owner without blocking the owner.

here is a codeexample of the codebehind part - I left out all obvious stuff:

namespace StackoverflowExample
{
  public partial class MainWindow : Window
  {
    public MainWindow()
    {
      InitializeComponent();
    }
    void NewWindowAsDialog(object sender, RoutedEventArgs e)
    {
      Window myOwnedDialog = new Window();
      myOwnedDialog.Owner = this;
      myOwnedDialog.ShowDialog();
    }
    void NormalNewWindow(object sender, RoutedEventArgs e)
    {
      Window myOwnedWindow = new Window();
      myOwnedWindow.Owner = this;
      myOwnedWindow.Show();
    }
  }
}

Solution 2:

Instead you can use a Popup that will be TopMost always, decorate it similar to a Window and to attach it completely with your Application handle the LocationChanged event of your main Window and set IsOpen property of Popup to false.

Edit:

I hope you want something like this:

    Window1 window;

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        window = new Window1();
        window.WindowStartupLocation = WindowStartupLocation.CenterScreen;
        window.Topmost = true;
        this.LocationChanged+=OnLocationchanged;
        window.Show();
    }
     
    private void OnLocationchanged(object sender, EventArgs e)
    {
          if(window!=null)
              window.Close();
    }

Hope it helps!!!

Solution 3:

CustomWindow cw = new CustomWindow();

cw.Owner = Application.Current.MainWindow;

cw.ShowInTaskbar = false;

cw.ShowDialog() ;