public: event System::Windows::Forms::PreviewKeyDownEventHandler ^ PreviewKeyDown; public event System.Windows.Forms.PreviewKeyDownEventHandler PreviewKeyDown; public event System.Windows.Forms.PreviewKeyDownEventHandler? PreviewKeyDown; member this.PreviewKeyDown : System.Windows.Forms.PreviewKeyDownEventHandler Public Custom Event PreviewKeyDown As PreviewKeyDownEventHandler イベントの種類 例 次のコード例は、 を