ModalDialog

A lookless modal dialog that displays arbitrary content centered over a host element using the WPF adorner layer. While open, the host is dimmed and optionally blurred, the dialog remains sharp, keyboard focus is cycled inside the dialog, and ShowAsync completes with the value passed to Close.

Basic usage

var dialog = new ModalDialog
{
    Title = "Delete item?",
    Description = "This action cannot be undone.",
    Content = new TextBlock
    {
        Text = "Add any WPF content here.",
        TextWrapping = TextWrapping.Wrap
    }
};

bool? result = await dialog.ShowAsync(Window.GetWindow(this)?.Content as UIElement ?? this);

Buttons inside the dialog can close it directly when you keep a reference to the dialog:

var confirm = new AccentButton { Content = "Delete" };
confirm.Click += (_, _) => dialog.Close(true);

For content that does not have the dialog reference, use ModalDialog.FindHost:

cancel.Click += (sender, _) =>
    ModalDialog.FindHost((DependencyObject)sender!)?.Close(false);

Key members

Member	Description
ShowAsync(UIElement host)	Shows the dialog over a loaded element with an adorner layer and returns the eventual bool? result.
Close(bool? result = null)	Dismisses the dialog and completes the task returned by ShowAsync.
FindHost(DependencyObject? element)	Walks up from a child element to find the containing ModalDialog.
Title	Header text displayed at the top of the dialog.
Description	Optional secondary text displayed under the title.
ShowCloseButton	Shows or hides the header close button.
CloseOnEscape	Allows Escape to close the dialog with a null result.
CloseOnBackdropClick	Allows clicking the dimmed backdrop to close the dialog with a null result.
BackdropBrush	Brush painted over the host while the dialog is open.
BlurRadius	Blur radius applied to the host. Set to 0 for dimming without blur.

Notes

The host passed to ShowAsync must be loaded and beneath an AdornerDecorator; normal WPF window content satisfies this by default. ModalDialog raises Opened after it is added to the adorner layer and Closed after it has been dismissed.