Events

Every event is a member of Menu, so you subscribe on the menu the item belongs to, not on the item. Lambdas and methods both work.

// Lambda
menu.OnMenuOpen += (_menu) => Debug.WriteLine("Opened!");

// Method group
menu.OnMenuOpen += HandleMenuOpen;

private void HandleMenuOpen(Menu menu)
{
    Debug.WriteLine($"'{menu.MenuTitle}' was opened.");
}

Which event fires for which item?

Item type	Pressing select	Pressing left / right
MenuItem	OnItemSelect	Right selects the item, left goes back to the parent menu.
MenuCheckboxItem	OnCheckboxChange	Right toggles the checkbox (raising `OnCheckboxChange`), left goes back to the parent menu.
MenuListItem	OnListItemSelect	OnListIndexChange
MenuDynamicListItem	OnDynamicListItemSelect	OnDynamicListItemCurrentItemChange
MenuSliderItem	OnSliderItemSelect	OnSliderPositionChange

Not tied to an item type: OnIndexChange, OnMenuOpen, OnMenuClose and OnPageChange.

Full example

Menu menu = new Menu("Main Menu", "Subtitle");
MenuController.AddMenu(menu);

MenuItem button = new MenuItem("Normal Button", "A simple button.");
MenuCheckboxItem box = new MenuCheckboxItem("Checkbox", "A checkbox.", false);
MenuListItem list = new MenuListItem("List", new List<string>() { "One", "Two", "Three" }, 0);

menu.AddMenuItem(button);
menu.AddMenuItem(box);
menu.AddMenuItem(list);

menu.OnItemSelect += (_menu, _item, _index) =>
{
    if (_item == button)
    {
        Debug.WriteLine("The normal button was pressed!");
    }
};

menu.OnCheckboxChange += (_menu, _item, _index, _checked) =>
{
    Debug.WriteLine($"'{_item.Text}' is now {(_checked ? "checked" : "unchecked")}.");
};

menu.OnListIndexChange += (_menu, _listItem, _oldIndex, _newIndex, _itemIndex) =>
{
    Debug.WriteLine($"List changed to '{_listItem.GetCurrentSelection()}'.");
};

menu.OnListItemSelect += (_menu, _listItem, _listIndex, _itemIndex) =>
{
    Debug.WriteLine($"'{_listItem.ListItems[_listIndex]}' was picked.");
};

menu.OnMenuOpen += (_menu) => Debug.WriteLine("Menu opened.");
menu.OnMenuClose += (_menu) => Debug.WriteLine("Menu closed.");

OnItemSelect

A MenuItem was pressed. For an item bound with MenuController.BindMenuItem(), this fires before the submenu opens. Disabled items never raise it, they play the error sound instead.

Parameter	Type	Description
menu	Menu	The menu in which this event occurred.
menuItem	MenuItem	The item that was pressed.
itemIndex	int	The index of that item in the menu.

menu.OnItemSelect += (_menu, _item, _index) =>
{
    // Comparing against the item you created is the most reliable check.
    if (_item == deleteButton)
    {
        DeleteTheThing();
    }

    // Or use ItemData when your items are created in a loop.
    if (_item.ItemData != null)
    {
        SpawnVehicle(_item.ItemData.model);
    }
};

OnCheckboxChange

A MenuCheckboxItem was toggled with select or right. Checked is already updated when this fires.

Parameter	Type	Description
menu	Menu	The menu in which this event occurred.
menuItem	MenuCheckboxItem	The checkbox that was toggled.
itemIndex	int	The index of that checkbox in the menu.
newCheckedState	boolean	The new checked state.

menu.OnCheckboxChange += (_menu, _item, _index, _checked) =>
{
    if (_item == godModeBox)
    {
        SetPlayerInvincible(Game.Player.Handle, _checked);
    }
};

OnListItemSelect

A MenuListItem was pressed with select. Changing its value with left or right does not raise this.

Parameter	Type	Description
menu	Menu	The menu in which this event occurred.
listItem	MenuListItem	The list item that was pressed.
selectedIndex	int	The selected index inside that list item’s `ListItems`.
itemIndex	int	The index of the list item in the menu.

menu.OnListItemSelect += (_menu, _listItem, _listIndex, _itemIndex) =>
{
    if (_listItem == weatherList)
    {
        SetWeather(_listItem.ListItems[_listIndex]);
    }
};

OnListIndexChange

The value of a MenuListItem was changed with left or right. Lists wrap around at both ends.

Parameter	Type	Description
menu	Menu	The menu in which this event occurred.
listItem	MenuListItem	The list item that was changed.
oldSelectionIndex	int	The previously selected index.
newSelectionIndex	int	The newly selected index.
itemIndex	int	The index of the list item in the menu.

// Live preview: update something as soon as the value changes.
menu.OnListIndexChange += (_menu, _listItem, _oldIndex, _newIndex, _itemIndex) =>
{
    if (_listItem == hairColors)
    {
        SetPedHairColor(PlayerPedId(), _newIndex, 0);
    }
};

OnSliderPositionChange

The position of a MenuSliderItem was changed with left or right. Sliders do not wrap: at Min or Max the error sound plays and this does not fire.

Parameter	Type	Description
menu	Menu	The menu in which this event occurred.
sliderItem	MenuSliderItem	The slider that was changed.
oldPosition	int	The previous slider position.
newPosition	int	The new slider position.
itemIndex	int	The index of the slider in the menu.

menu.OnSliderPositionChange += (_menu, _sliderItem, _oldPosition, _newPosition, _itemIndex) =>
{
    if (_sliderItem == volumeSlider)
    {
        SetVolume(_newPosition / 10f);
    }
};

OnSliderItemSelect

A MenuSliderItem was pressed with select.

Parameter	Type	Description
menu	Menu	The menu in which this event occurred.
sliderItem	MenuSliderItem	The slider that was pressed.
sliderPosition	int	The current slider position.
itemIndex	int	The index of the slider in the menu.

OnDynamicListItemCurrentItemChange

The value of a MenuDynamicListItem was changed with left or right. Fires right after the item’s callback returned the new value.

Parameter	Type	Description
menu	Menu	The menu in which this event occurred.
dynamicListItem	MenuDynamicListItem	The dynamic list item that was changed.
oldValue	string?	The value before the change.
newValue	string	The value the callback returned.

menu.OnDynamicListItemCurrentItemChange += (_menu, _item, _oldValue, _newValue) =>
{
    Debug.WriteLine($"'{_item.Text}' changed from {_oldValue} to {_newValue}.");
};

OnDynamicListItemSelect

A MenuDynamicListItem was pressed with select.

Parameter	Type	Description
menu	Menu	The menu in which this event occurred.
dynamicListItem	MenuDynamicListItem	The dynamic list item that was pressed.
currentItem	string?	The value currently displayed.

OnIndexChange

The highlighted item changed, by up, down or the scroll wheel. The list wraps around at both ends. It does not fire in a menu with fewer than 2 items.

Parameter	Type	Description
menu	Menu	The menu in which this event occurred.
oldItem	MenuItem	The item that was highlighted before.
newItem	MenuItem?	The item that is highlighted now. Can be null.
oldIndex	int	The previous index.
newIndex	int	The new index.

// Load a preview of whatever the user is currently looking at.
menu.OnIndexChange += (_menu, _oldItem, _newItem, _oldIndex, _newIndex) =>
{
    if (_newItem?.ItemData != null)
    {
        PreviewVehicle(_newItem.ItemData.model);
    }
};

OnMenuOpen

The menu was opened, by the player or by Menu.OpenMenu().

Parameter	Type	Description
menu	Menu	The menu that was opened.

// Refresh the contents every time the menu is opened.
menu.OnMenuOpen += (_menu) =>
{
    _menu.ClearMenuItems();
    BuildItems(_menu);
};

OnMenuClose

The menu was closed, by the player or by Menu.CloseMenu(), Menu.GoBack() or MenuController.CloseAllMenus().

Parameter	Type	Description
menu	Menu	The menu that was closed.

menu.OnMenuClose += (_menu) =>
{
    SaveSettings();
};

Delegate signatures

All delegate types are nested in Menu.

Event	Delegate
OnItemSelect	`void ItemSelectEvent(Menu menu, MenuItem menuItem, int itemIndex)`
OnCheckboxChange	`void CheckboxItemChangeEvent(Menu menu, MenuCheckboxItem menuItem, int itemIndex, bool newCheckedState)`
OnListItemSelect	`void ListItemSelectedEvent(Menu menu, MenuListItem listItem, int selectedIndex, int itemIndex)`
OnListIndexChange	`void ListItemIndexChangedEvent(Menu menu, MenuListItem listItem, int oldSelectionIndex, int newSelectionIndex, int itemIndex)`
OnSliderPositionChange	`void SliderPositionChangedEvent(Menu menu, MenuSliderItem sliderItem, int oldPosition, int newPosition, int itemIndex)`
OnSliderItemSelect	`void SliderItemSelectedEvent(Menu menu, MenuSliderItem sliderItem, int sliderPosition, int itemIndex)`
OnDynamicListItemCurrentItemChange	`void DynamicListItemCurrentItemChangedEvent(Menu menu, MenuDynamicListItem dynamicListItem, string? oldValue, string newValue)`
OnDynamicListItemSelect	`void DynamicListItemSelectedEvent(Menu menu, MenuDynamicListItem dynamicListItem, string? currentItem)`
OnIndexChange	`void IndexChangedEvent(Menu menu, MenuItem oldItem, MenuItem? newItem, int oldIndex, int newIndex)`
OnMenuOpen	`void MenuOpenedEvent(Menu menu)`
OnMenuClose	`void MenuClosedEvent(Menu menu)`
OnPageChange	`void PageChangedEvent(Menu menu, int oldPage, int newPage, bool wrapped)`