WPF: Always-open Window and Modal Dialoges

Question

I have a help window in my application that can be opened at any time in the application. The main window of my application is a wizard window that opens modal dialogues and also the aforementioned non-modal help window. It should be possible to keep the help window open and accessible as long as the user needs help - from the wizard and from any modal dialog opened by the wizard.

When opening the help window in the main window first and opening a modal dialog afterwards, the help window behaves like it is owned by the main window and on the same hierarchy level - it is getting disabled. When opening the help window in the modal dialog first and closing the modal dialog afterwards, the help window is enabled in the main window. So it seems the help window is always getting tied to the currently modal dialog somehow, but is still accessible from any modal parent windows.

I've managed to resolve the problem by hiding and re-show the help window as soon as a modal dialog opens. Are there any other solutions to keep the help window enabled when opening a modal dialog? The TopMost property had no effect on the behavior.

I guess this is a general modal dialog behavior in Windows, but I'm currently using WPF for my application.

Thanks in advance for your input!

P

Bizhan Bizhan · Accepted Answer · 2014-11-23T10:14:01

If it's just a help window why take the long road?

Create a Help project and use its exe file as a separate process. This way the modal window won't block your help window:

System.Diagnostics.Process.Start("HelpWindow.exe");

Edit

Another workaround is to embed all modal windows within the same window so that only the main content would be prevented from being clicked:

<MainWindow>
    <Grid>
        <!-- main content of main window -->
        <local:MyMainUC/>

        <!-- any messageBox, modal window or dialog here -->
        <Border Background="#2000" Visibility="Collapsed">
            <local:MyDialogUC HorizontalAlignment="Center" VerticalAlignment="Center"/>
        </Border>
        <Border Background="#2000" Visibility="Collapsed">
            <local:MyMessageBox HorizontalAlignment="Center" VerticalAlignment="Center"/>
        </Border>
    </Grid>
</MainWindow>

So instead of window.ShowDialog() you just change the Visibility of a border.

WPF: Always-open Window and Modal Dialoges

1 Answers

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