User Interface Event Handlers

User Interface Event handlers allow you to automatically monitor and then execute custom code upon particular UI events being triggered.

Reference List

!	When using the event names listed below with the ctrlAddEventHandler, ctrlSetEventHandler, displayAddEventHandler or displaySetEventHandler commands, the prefix "on" in the name must be removed. (e.g. 'ButtonDown' instead of 'onButtonDown')

Priority	Event	Fired	Notes and Parameters	Scope
1	onLoad	Display and all controls are created, but no action on any is taken.	Returns the display.	Display
1	onUnload	Display is closed, but no controls are destroyed yet.	Returns the display and exit code.	Display
1	onChildDestroyed	Child display is closed.	Returns the display, which child display was closed and exit code.	Display
1	onMouseEnter	The mouse pointer enters the control area.	Returns control.	Control
1	onMouseExit	The mouse pointer exits the control area.	Returns control.	Control
2	onSetFocus	Input focus is on control. It now begins to accept keyboard input.	Returns control.	Control
2	onKillFocus	Input focus is no longer on control. It no longer accepts keyboard input.	Returns control.	Control
3	onTimer	After amount of time given by setTimer function.	Returns control.	Control
2	onKeyDown	Pressing any keyboard key. Fired before the onKeyUp event.	Returns the control, the keyboard code and the state of Shift, Ctrl and Alt.	Display, Control
2	onKeyUp	Releasing any keyboard key. Fired after the onKeyDown event.	Returns the control, the keyboard code and the state of Shift, Ctrl and Alt.	Display, Control
2	onChar	When some readable characters is recognised.	Returns the control and the char code.	Control
2	onIMEChar	When IME character is recognized (used in Korean and other eastern languages).	Returns the control and the char code.	Control
2	onIMEComposition	When partial IME character is recognized (used in Korean and other eastern languages).	Returns the control and the char code.	Control
3	onJoystickButton	Pressing and releasing any joystick button.	Not in Arma 2 or Arma 3 Returns the control and the the pressed button.	Control
2	onMouseButtonDown	Pressing a mouse button. Followed by the onMouseButtonUp event.	Returns the control, the pressed button, the x and y coordinates and the state of Shift, Ctrl and Alt.	Control
2	onMouseButtonUp	Releasing a mouse button. Follows the onMouseButtonDown event.	Returns the control, the pressed button, the x and y coordinates and the state of Shift, Ctrl and Alt.	Control
2	onMouseButtonClick	Pressing and releasing a mouse button.	Returns the control, the pressed button, the x and y coordinates and the state of Shift, Ctrl and Alt.	ListBox, ComboBox, TextBox, Button, ActiveText
2	onMouseButtonDblClick	Pressing and releasing a mouse button twice within very short time.	Returns the control, the pressed button, the x and y coordinates and the state of Shift, Ctrl and Alt.	Control
2	onMouseMoving	Fires continuously while moving the mouse with a certain interval.	Returns the control, the x and y coordinates relative to control and mouseOver.	Control
			Returns the display, the some kind of x and y delta position.	Display
2	onMouseHolding	Fires continuously while mouse is not moving with a certain interval.	Returns the control, the x and y coordinates and mouseOver. If used with a display, the mouseOver parameter is excluded.	Control
2	onMouseZChanged	Fires when mouse wheel position is changed. Does not fire on disabled control. Checked with CT_EDIT type in v1.50.	Returns the control and the change of the scrollbar.	Control only
3	onCanDestroy	Ask this control if dialog can be closed (used for validation of contained data).	Returns the control and exit code.	Control
3	onDestroy	Destroying control	Returns the control and exit code.	Control
1	onButtonClick	The attached button action is performed. When returned value is true, button's display remains opened.	Returns control.	Button
?	onButtonDblClick	?	Arma 3	Button
1	onButtonDown	The left mouse button is pressed over the button area or a key on the keyboard is pressed.	Returns control.	Button
1	onButtonUp	The left mouse buttons is released outside the button area and the attached button action is not performed.	Returns control.	Button
2	onLBSelChanged	The selection in a listbox is changed. The left mouse button has been released and the new selection is fully made.	Returns the control and the selected element index.	Listbox
2	onLBListSelChanged	Selection in XCombo box changed (but value is not stored yet).	Returns the control and the selected element index.	Listbox
2	onLBDblClick	Double click on some row in listbox.	Returns the control and the selected element index.	Listbox
2	onLBDrag	Drag & drop operation started.	Returns the control and the selected element index.	Listbox
2	onLBDragging	Drag & drop operation is in progress.	Returns the control and the x and y coordinates.	Listbox
2	onLBDrop	Drag & drop operation finished.	Returns the control and the x and y coordinates.	Listbox, Combobox, Textbox, ActiveText, Button
2	onTreeSelChanged	Changing the selection in a tree.	Returns the control and the new selection path.	Tree
2	onTreeLButtonDown	Pressing and releasing left mouse button on a tree.	Returns the control.	Tree
2	onTreeDblClick	Pressing and releasing twice on a tree entry.	Returns the control and the current selection path.	Tree
3	onTreeExpanded	The tree folder structure has been expanded.	Returns the control.	Tree
3	onTreeCollapsed	The tree folder structure has been collapsed.	Returns the control.	Tree
2	onTreeMouseMove	Fires continuously while moving the mouse with a certain interval.	Returns the control.	Tree
2	onTreeMouseHold	Fires continuously while mouse is not moving with a certain interval.	Returns the control.	Tree
2	onTreeMouseExit	The mouse pointer exits the tree control area	Returns the control.	Tree
2	onToolBoxSelChanged	Changed the selection in a toolbox.	Returns the control and the selected element index.	Toolbox
?	onChecked	?	Arma 3	Checkbox
?	onCheckedChanged	Checked state of CheckBox changed.	Arma 3. Returns control and the checked state.	Checkbox
2	onCheckBoxesSelChanged	Changed the selection in a checkbox.	Returns the control, the selected element index and the current state.	Checkbox
2	onHTMLLink	Pressing and releasing a HTML link.	Returns the control and href.	HTML
2	onSliderPosChanged	Changing the position of a slider.	Returns the control and the change.	Slider
2	onObjectMoved	Moving an object.	Returns the control and the offset on the x, y and z axes.	Object
2	onMenuSelected	Some item in context menu (used now only in new mission editor) was selected.	Returns the control and the command id.	Context menu
?	onDraw	Fires when the map is drawn (can occur more than once per second).	Returns the map control.	Map
2	onVideoStopped	Introduced with Arma 2: Operation Arrowhead version 1.56 Activated every time video ends (when looped, handler is executed after every finished loop).	Returns the control	Control

Event parameters

The events handlers receive parameters in the _this variable. Each event passes a different set of parameters (listed in the table above) in an array. The control or display that the event was assigned to is always found in _this select 0.

Scope

In ArmA, most control-specific events work for controls and do not work for displays. The 2 exceptions being: onKeyDown and onKeyUp.

Since Arma 2, most control-specific events now work for both displays and controls.

Defining events

User Interface Event Handlers can be assigned in two ways: via class property definitions or via scripting commands.

Class defined events

Events can be defined in the Dialog (display) or Control classes (in config.cpp or description.ext). The event property value (string) is executed as a line of code. An example line (this would be put within a control or dialog class):

onMouseDown = "hint str _this";

Example:

class RscControlsGroup {
    type = 15;
    idc = -1;
    style = 0;
    x = 0;
    y = 0;
    w = 1;
    h = 1;
    
    class VScrollbar {
        color[] = {1,1,1,1};
        width = 0.021000;
        autoScrollSpeed = -1;
        autoScrollDelay = 5;
        autoScrollRewind = 0;
    };
    
    class HScrollbar {
        color[] = {1, 1, 1, 1};
        height = 0.028;
    };

    class ScrollBar { //for ARMA 2
        color[] = {1,1,1,0.600000};
        colorActive[] = {1,1,1,1};
        colorDisabled[] = {1,1,1,0.300000};
        thumb = "#(argb,8,8,3)color(1,1,1,1)";
        arrowEmpty = "#(argb,8,8,3)color(1,1,1,1)";
        arrowFull = "#(argb,8,8,3)color(1,1,1,1)";
        border = "#(argb,8,8,3)color(1,1,1,1)";
    };
    
    class Controls {};
};

class mouseHandler: RscControlsGroup {          
    onMouseHolding = "[0,_this] call Axx";
    onMouseButtonDown = "[1,_this] call Axx";
    onMouseButtonUp = "[2,_this] call Axx";
    onMouseZChanged = "[3,_this] call Axx";    
    onMouseEnter = "[4,_this] call Axx";    
    idc = 123;
    x = 0.0;
    y = 0.0;
    w = 1.0;
    h = 1.0;            
    colorBackground[] = {0.2, 0.0, 0.0, 0.0};
};

Script defined events

These events can also be given to dialogs/controls using the ctrlSetEventHandler scripting command. For the event handler to be called enable the control using the ctrlEnable scripting command.

(findDisplay 46) displayAddEventHandler ["keyDown", "_this call functionName_keyDown"];

functionName_keyDown = {   params ["_ctrl", "_dikCode", "_shift", "_ctrlKey", "_alt"];     private _handled = false;     if (!_shift && !_ctrlKey && !_alt) then {   if (_dikCode in (actionKeys "NetworkStats")) then {   [] execVM "path\script.sqf";   _handled = true;   };   };     _handled; };

Demo mission

For VBS2 users, a demo mission is available here.