{"name":"addUserActionEventHandler","title":"addUserActionEventHandler","type":"command","url":"https://community.bistudio.com/wiki/addUserActionEventHandler","revid":378187,"updated":"2026-03-10T13:05:46Z","groups":["Event Handlers"],"status":"ok","games":{"arma3":"2.06"},"since":"arma3 2.06","arma3_since":"2.06","locality":{"effect":"local"},"description":"Adds a user action event handler to the current mission and returns its event handler index.","syntaxes":[{"syntax":"addUserActionEventHandler [keyName, event, expression]","params":[{"name":"keyName","type":"String","description":"action key name - see inputAction/actions","type_expr":"String"},{"name":"event","type":"String","description":"event name - see UserAction Event Handlers. Can be one of:\n\n- `\"Activate\"`\n- `\"Deactivate\"`\n- `\"Analog\"`","type_expr":"String"},{"name":"expression","type":"Code","description":"expression that will be executed in missionNamespace when event handler fires.\n\n- `_thisEventHandler` returns the event handler index\n- `_thisEvent` returns the event type (the *event* parameter, either `\"Activate\"`, `\"Deactivate\"` or `\"Analog\"`)","type_expr":"Code"}],"returns":{"type":"Number","type_expr":"Number","description":"the index of the currently added UserAction event handler is returned"},"form":"unary","right":{"text":"[keyName, event, expression]"}}],"examples":[{"code":["private _ehId = addUserActionEventHandler [\"ReloadMagazine\", \"Activate\", { systemChat \"reloading!\"; }];"]}],"see_also":["removeUserActionEventHandler","removeAllUserActionEventHandlers","Arma 3: Event Handlers"]}