Instance Method


Runs the alert modally as a sheet attached to the specified window.


func beginSheetModal(for sheetWindow: NSWindow, completionHandler handler: ((NSApplication.ModalResponse) -> Void)? = nil)



The window on which to display the sheet.


The completion handler that gets called when the sheet’s modal session ends.


This method uses the NSWindow sheet methods to display the alert (for more information, see Managing Sheets). If the alert has an alert style of NSCriticalAlertStyle, it is presented as a critical sheet, which means that it can display on top of other sheets that might already be attached to the window. Otherwise, it is presented—or queued for presentation—as a standard sheet.

Note that orderOut(_:) no longer needs to be called in the completion handler. If you don’t dismiss the alert, it will be done for you after the completion handler finishes.

See Also

Displaying Alerts

func runModal() -> NSApplication.ModalResponse

Runs the alert as an app-modal dialog and returns the constant that identifies the button clicked.

func beginSheetModal(for: NSWindow, modalDelegate: Any?, didEnd: Selector?, contextInfo: UnsafeMutableRawPointer?)

Runs the alert modally as an alert sheet attached to a specified window.

var suppressionButton: NSButton?

The alert’s suppression checkbox.

var showsSuppressionButton: Bool

Specifies whether the alert includes a suppression checkbox, which you can employ to allow a user to opt out of seeing the alert again.