FarsiLibrary.WPF.Controls.FXDatePicker.KeyDownHandler C# (CSharp) Метод

        private void KeyDownHandler(KeyEventArgs e)
        {
            bool handled = false;
            Key key = e.Key;

            // Only process key events if they haven't been handled or are from our text box
            if (e.Handled == false)
            {
                // We want to handle Alt key. Get the real key if it is Key.System.
                if (key == Key.System)
                {
                    key = e.SystemKey;
                }

                switch (key)
                {
                    case Key.Up:
                        if ((e.KeyboardDevice.Modifiers & ModifierKeys.Alt) == ModifierKeys.Alt)
                        {
                            KeyboardToggleDropDown(!IsDropDownOpen, true /* commitSelection */);
                            handled = true;
                        }
                        break;

                    case Key.Down:
                        if ((e.KeyboardDevice.Modifiers & ModifierKeys.Alt) == ModifierKeys.Alt)
                        {
                            KeyboardToggleDropDown(!IsDropDownOpen, true /* commitSelection */);
                            handled = true;
                        }
                        else if (IsDropDownOpen)
                        {
                            SelectFocusableDate();
                            handled = true;
                        }
                        break;

                    case Key.F4:
                        if ((e.KeyboardDevice.Modifiers & ModifierKeys.Alt) == 0)
                        {
                            KeyboardToggleDropDown(!IsDropDownOpen, true /* commitSelection */);
                            handled = true;
                        }
                        break;

                    case Key.Escape:
                        if (IsDropDownOpen)
                        {
                            KeyboardToggleDropDown(false, false /* commitSelection */);
                            handled = true;
                        }
                        break;

                    case Key.Enter:
                        if (IsDropDownOpen)
                        {
                            KeyboardToggleDropDown(false, true /* commitSelection */);
                            handled = true;
                        }
                        break;

                    case Key.Tab:
                        if (IsDropDownOpen)
                        {
                            IsDropDownOpen = false;
                        }
                        break;

                    default:
                        break;
                }

                if (handled)
                {
                    e.Handled = true;
                }
            }
        }