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EventHandler

EventHandler[expr, {"event₁":>action₁, "event₂":>action₂, ...}]
displays as expr, evaluating action_i whenever "event_i" occurs in connection with expr.

MORE INFORMATION

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 action_i, the values they give are those associated with the event that triggered that action_i.

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:

	PassEventsDown	Automatic	whether to pass events to inner event handlers
	PassEventsUp	True	whether to pass events to outer event handlers

With the default setting PassEventsDown->Automatic, events handled by an EventHandler are not also passed to built-in event handlers in the Mathematica front end.

Basic Examples (2)

Create text that turns red when clicked:

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

Applications (2)

Properties & Relations (1)

Mouseover Button ClickPane LocatorPane CurrentValue Manipulate MousePosition CellEventActions NotebookEventActions FrontEndEventActions ControlActive

Introduction to Dynamic

Advanced Dynamic Functionality

Demonstrations with EventHandler (Wolfram Demonstrations Project)

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