NSOpenPanel

NSOpenPanel is a class in Apple's AppKit framework that presents the standard macOS file-open dialog. It is used by Cocoa applications to prompt the user to select one or more files or directories. NSOpenPanel is the counterpart to NSSavePanel, together providing the system file dialogs.

Instances of NSOpenPanel can be configured to restrict selection, offer multi-select, and customize file types. Common properties include canChooseFiles, canChooseDirectories, and allowsMultipleSelection. Other options include canCreateDirectories, title and prompt, directoryURL for the initial folder, and allowedContentTypes or allowedFileTypes to filter selectable items.

To use it, create an NSOpenPanel, apply desired settings, and present it either as a modal window (runModal) or as a sheet attached to a window (beginSheetModal(for:completionHandler:)). If the user confirms, panel.urls contains the selected file URLs for processing. The operation returns a modal response indicating success or cancellation.

NSOpenPanel supports delegates and is accessible from Objective-C and Swift. It is a standard component in macOS applications, used for document opening, image selection, and other file-based workflows.