Microsoft.Windows.Controls.Ribbon.RibbonMenuButton.OnPreviewKeyDown C# (CSharp) Метод

        protected override void OnPreviewKeyDown(KeyEventArgs e)
        {
            HandleSpaceEnterUp = false;
            if (e.OriginalSource == _partToggleButton ||
                e.OriginalSource == this)
            {
                if (e.Key == Key.Space ||
                    e.Key == Key.Enter)
                {
                    // Do not let _partToggleButton handle space and enter.
                    // This is because it will open dropdown on space/enter
                    // down where as we need to open on key up.
                    HandleSpaceEnterUp = true;
                    e.Handled = true;
                }
            }
            base.OnPreviewKeyDown(e);
        }