Wolfram Language & System 11.0 (2016)|Legacy Documentation

This is documentation for an earlier version of the Wolfram Language.View current documentation (Version 11.2)

This feature is not supported on the Wolfram Cloud.

displays as expr, evaluating actioni whenever "eventi" occurs in connection with expr.

Details and OptionsDetails and Options

  • Standard mouse-related event specifications include:
  • "MouseClicked"mouse clicked without moving
    {"MouseClicked",i}mouse button i clicked without moving
    "MouseDown"primary mouse button depressed
    {"MouseDown",i}mouse button i depressed
    "MouseDragged"mouse moving with primary button depressed
    {"MouseDragged",i}mouse moving with button i depressed
    "MouseMoved"mouse moves in the region defined by expr
    "MouseUp"primary mouse button released
    {"MouseUp",i}mouse button i released
  • For mouse events, EventHandler[expr, ] handles events for which the mouse is within the rectangular region defined by the display of expr.
  • Standard keyboard-related event specifications include:
  • "KeyDown"any key on the keyboard depressed
    {"KeyDown","x"}key x depressed
    "ReturnKeyDown"Return or Enter key depressed
    "EscapeKeyDown"Esc key depressed
    "LeftArrowKeyDown"left arrow key depressed
    "RightArrowKeyDown"right arrow key depressed
    "UpArrowKeyDown"up arrow key depressed
    "DownArrowKeyDown"down arrow key depressed
  • Standard interface events include:
  • {"MenuCommand","name"}menu command with specified name chosen
    "WindowClose"closing of window requested
  • If functions like MousePosition or CurrentValue are evaluated in a particular actioni, the values they give are those associated with the event that triggered that actioni.
  • When EventHandler expressions are nested, events are by default shared by all the expressions, with the innermost expression operating first on a particular event.
  • The following options can be given:
  • Method"Preemptive"the evaluation method to use
    PassEventsDownAutomaticwhether to pass events to inner event handlers
    PassEventsUpTruewhether to pass events to outer event handlers
  • Typical possible settings for the Method option include "Preemptive" and "Queued".
  • With the default setting PassEventsDown->Automatic, events handled by an EventHandler are not also passed to built-in event handlers in the Wolfram System front end.

ExamplesExamplesopen allclose all

Basic Examples  (3)Basic Examples  (3)

Create text that turns red when clicked:

Click for copyable input

Create text that toggles between red and green when clicked repeatedly:

Click for copyable input
Introduced in 2007