FlaUI Prism Dialog Discovery

FlaUI Prism Dialog Discovery

Prism's IDialogAware dialogs in WPF-UI applications often use custom window styles (TitlelessWindow, CommonWindow) that make standard FlaUI modal discovery unreliable. This skill covers patterns for finding and verifying these dialogs.

Problem: TitlelessWindow Modals Can't Be Found by Title

Prism dialogs using TitlelessWindow style have no Title property. Standard modal search by title returns nothing.

Symptoms:

• _mainWindow.ModalWindows returns windows but modal.Title is empty
• Dialog is visually present but can't be distinguished from other titleless modals
• Multiple titleless modals may exist simultaneously

Fix — identify by child control type:

/// <summary>
/// Finds a Progress dialog by looking for a modal with a ProgressBar control.
/// TitlelessWindow style means Title is empty, so we identify by content.
/// </summary>
private AutomationElement? FindProgressDialog()
{
    var modalWindows = _mainWindow.ModalWindows;
    foreach (var modal in modalWindows)
    {
        var progressBar = modal.FindFirstDescendant(cf =>
            cf.ByControlType(ControlType.ProgressBar));

        if (progressBar is not null)
        {
            return modal;
        }
    }

    return null;
}

For titled dialogs (CommonWindow with Title):

/// <summary>
/// Finds a modal dialog with a non-empty Title (e.g., warning, confirmation).
/// </summary>
private AutomationElement? FindTitledModal()
{
    var modalWindows = _mainWindow.ModalWindows;
    foreach (var modal in modalWindows)
    {
        if (!string.IsNullOrEmpty(modal.Title))
        {
            return modal;
        }
    }

    return null;
}

General pattern — identify modal by unique child:

private AutomationElement? FindModalByChild(
    Func<AutomationElement, bool> childMatcher)
{
    foreach (var modal in _mainWindow.ModalWindows)
    {
        var descendants = modal.FindAllDescendants();
        if (descendants.Any(childMatcher))
        {
            return modal;
        }
    }

    return null;
}

// Usage: find modal containing a specific button text
var dialog = FindModalByChild(d =>
    d.Name?.Contains("Cancel", StringComparison.OrdinalIgnoreCase) == true);

Problem: Verifying ESC Key Cancellation

WPF buttons with IsCancel="True" close the dialog on ESC press. In Prism dialogs, this triggers IDialogAware.OnDialogClosed(). Testing this requires verifying both dialog closure and the application's response.

Pattern — ESC cancel with Status Bar verification:

// 1. Wait for dialog to appear
var dialog = RetryHelper.WaitForElement(
    () => FindProgressDialog(),
    TimeSpan.FromSeconds(10));
Assert.NotNull(dialog);

// 2. Press ESC (triggers IsCancel="True" button → CancelCommand)
Thread.Sleep(500); // Allow dialog to fully render
Keyboard.Press(VirtualKeyShort.ESCAPE);

// 3. Verify dialog closed
var closed = RetryHelper.WaitUntil(
    () => FindProgressDialog() is null,
    TimeSpan.FromSeconds(10));
Assert.True(closed, "ESC should close the dialog");

// 4. Verify cancellation via Status Bar message
// This distinguishes cancel from normal completion
var statusVerified = RetryHelper.WaitUntil(
    () =>
    {
        var texts = _mainWindow.FindAllDescendants(cf =>
            cf.ByControlType(ControlType.Text));
        return texts.Any(t =>
            t.Name?.Contains("canceled", StringComparison.OrdinalIgnoreCase) == true);
    },
    TimeSpan.FromSeconds(5));
Assert.True(statusVerified, "Status Bar should show 'canceled' message");

Why Status Bar verification matters:

• Dialog closes on Success, Failure, AND Cancel — closure alone doesn't prove cancellation
• ProgressBar value < 100% is unreliable (fast tasks may complete before ESC)
• Status Bar message is set by VisionTaskCompleted(TaskEventReason.Canceled) event — unique to cancellation

Problem: File Open Dialog Interaction

Loading test data via Ctrl+O requires interacting with the Windows file dialog, which is a separate process.

Pattern:

// Ctrl+O to open file dialog
DragHelper.ForceSetForeground(_mainWindow);
Thread.Sleep(300);
Keyboard.TypeSimultaneously(VirtualKeyShort.CONTROL, VirtualKeyShort.KEY_O);
Thread.Sleep(2000); // File dialog takes time to open

// Type file path and confirm
Keyboard.TypeSimultaneously(VirtualKeyShort.CONTROL, VirtualKeyShort.KEY_A);
Thread.Sleep(100);
Keyboard.Type(taskConfigPath);
Thread.Sleep(500);
Keyboard.Type(VirtualKeyShort.ENTER);
Thread.Sleep(3000); // Loading takes time

// Handle potential warning dialog (e.g., path validation)
var warningDialog = FindTitledModal();
if (warningDialog is not null)
{
    Keyboard.Type(VirtualKeyShort.ENTER); // Dismiss warning
    Thread.Sleep(500);
}

Prism Dialog Window Styles Reference

Style	Title	How to Find
CommonWindow (default)	Set via prism:Dialog.WindowStyle Setter	modal.Title
TitlelessWindow	Empty	Child control type (ProgressBar, specific Button, etc.)
CommonWindow with no Title Setter	Empty	Same as TitlelessWindow

Key Timing Considerations

• Thread.Sleep(2000) after Ctrl+O — Windows file dialog is cross-process, needs extra time
• Thread.Sleep(3000) after ENTER in file dialog — task config loading + FunctionBlock instantiation
• Thread.Sleep(500) before ESC — allow dialog to fully render and receive keyboard focus
• Use RetryHelper.WaitUntil for state verification instead of fixed sleep