OnElementDataChange - Revision history

Arran Fortuna: Added info about being able to cancel the event.

2025-10-07T19:30:34Z

Added info about being able to cancel the event.

← Older revision		Revision as of 19:30, 7 October 2025
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	==Cancelling==		==Cancelling==
	This event cannot be cancelled using [[cancelEvent]]. To reverse the effect, use [[setElementData]] with the old value. See Example.		This event cannot be cancelled using [[cancelEvent]]. To reverse the effect, use [[setElementData]] with the old value. See Example.

			{{New items\|3.0170\|1.7.0\|
			This event can be cancelled using [[cancelEvent]]. If a client sent the cancelled change to the server, the server will send the client the server's version of the element data.
			\|25731}}

	==Source==		==Source==
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	outputChatBox("Illegal setting of " .. tostring(theKey) .. "' by '" .. tostring(getPlayerName(client)))		outputChatBox("Illegal setting of " .. tostring(theKey) .. "' by '" .. tostring(getPlayerName(client)))
	setElementData(source, theKey, oldValue) -- Set back the original value		setElementData(source, theKey, oldValue) -- Set back the original value
			end
			end
			addEventHandler("onElementDataChange", root, checkChange)
			</syntaxhighlight>
			This example blocks all element data changes from clients. In MTA 1.7+ only.
			<syntaxhighlight lang="lua">
			function checkChange(theKey, oldValue, newValue)
			if (client) then -- if there's a client variable, it means it came from a player.
			cancelEvent()
	end		end
	end		end

Fernando187: formatting for global parameters

2025-06-01T15:11:57Z

formatting for global parameters

← Older revision		Revision as of 15:11, 1 June 2025
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	__NOTOC__		__NOTOC__
	This event is triggered ''after'' an element's [[element data\|data]] entry is changed. Such changes can be made on the client or the server using [[setElementData]].		This event is triggered ''after'' an element's [[element data\|data]] entry is changed. Such changes can be made on the client or the server using [[setElementData]].

			{{Note\|These predefined variables are special in this event:
			*'''client''': The [[event system#Event client\|client]] global variable is set to the client that called [[setElementData]], or '''nil''' if it was called on the server.
			*'''sourceResource''': The [[resource]] which changed the element data - '''nil''', if client synced data, '''resource''' element otherwise.}}

	==Parameters==		==Parameters==
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	*'''oldValue''': The old value of this entry before it changed. See [[element data]] for a list of possible datatypes.		*'''oldValue''': The old value of this entry before it changed. See [[element data]] for a list of possible datatypes.
	*'''newValue''': the new value of this entry after it changed. This will be equivalent to [[getElementData]](source, theKey).		*'''newValue''': the new value of this entry after it changed. This will be equivalent to [[getElementData]](source, theKey).

	~~==Global parameters==~~
	*'''client''': The [[event system#Event client\|client]] global variable is set to the client that called [[setElementData]], or '''nil''' if it was called on the server.
	*'''sourceResource''': The [[resource]] which changed the element data - '''nil''', if client synced data, '''resource''' element otherwise.

	==Cancelling==		==Cancelling==

Fernando187: /* Source */

2025-05-31T13:01:52Z

Source

← Older revision		Revision as of 13:01, 31 May 2025
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	==Source==		==Source==
	The source of this ~~any~~ [[element]] ~~that supports~~ element data.		The source of this event is the [[element]] whose element data changed.

	==Example==		==Example==

Fernando187: /* Global parameters */

2025-05-31T13:01:39Z

Global parameters

← Older revision		Revision as of 13:01, 31 May 2025
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	==Global parameters==		==Global parameters==
	*'''source''': The [[event system#Event source\|source]] of this event is the [[element]] whose [[element data]] changed.
	*'''client''': The [[event system#Event client\|client]] global variable is set to the client that called [[setElementData]], or '''nil''' if it was called on the server.		*'''client''': The [[event system#Event client\|client]] global variable is set to the client that called [[setElementData]], or '''nil''' if it was called on the server.
	*'''sourceResource''': The [[resource]] which changed the element data - '''nil''', if client synced data, '''resource''' element otherwise.		*'''sourceResource''': The [[resource]] which changed the element data - '''nil''', if client synced data, '''resource''' element otherwise.

Fernando187 at 16:16, 29 May 2025

2025-05-29T16:16:25Z

← Older revision		Revision as of 16:16, 29 May 2025
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	==Cancelling==		==Cancelling==
	This event cannot be cancelled using [[cancelEvent]]. To reverse the effect, use [[setElementData]] with the old value. See Example.		This event cannot be cancelled using [[cancelEvent]]. To reverse the effect, use [[setElementData]] with the old value. See Example.

			==Source==
			The source of this any [[element]] that supports element data.

	==Example==		==Example==
	<section name="Server" class="server" show="true">		<section name="Server" class="server" show="true">

Srslyyyy: Add comma

2023-06-07T18:17:21Z

Add comma

← Older revision		Revision as of 18:17, 7 June 2023
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	*'''source''': The [[event system#Event source\|source]] of this event is the [[element]] whose [[element data]] changed.		*'''source''': The [[event system#Event source\|source]] of this event is the [[element]] whose [[element data]] changed.
	*'''client''': The [[event system#Event client\|client]] global variable is set to the client that called [[setElementData]], or '''nil''' if it was called on the server.		*'''client''': The [[event system#Event client\|client]] global variable is set to the client that called [[setElementData]], or '''nil''' if it was called on the server.
	*'''sourceResource''': The [[resource]] which changed the element data - '''nil''' if client synced data, '''resource''' element otherwise.		*'''sourceResource''': The [[resource]] which changed the element data - '''nil''', if client synced data, '''resource''' element otherwise.

	==Cancelling==		==Cancelling==

Srslyyyy: Bold some data.

2023-06-07T18:16:58Z

Bold some data.

← Older revision		Revision as of 18:16, 7 June 2023
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	==Global parameters==		==Global parameters==
	*'''source''': The [[event system#Event source\|source]] of this event is the [[element]] whose [[element data]] changed.		*'''source''': The [[event system#Event source\|source]] of this event is the [[element]] whose [[element data]] changed.
	*'''client''': The [[event system#Event client\|client]] global variable is set to the client that called [[setElementData]], or nil if it was called on the server.		*'''client''': The [[event system#Event client\|client]] global variable is set to the client that called [[setElementData]], or '''nil''' if it was called on the server.
	*'''sourceResource''': The [[resource]] which changed the element data - '''nil''' if client synced data, resource otherwise.		*'''sourceResource''': The [[resource]] which changed the element data - '''nil''' if client synced data, '''resource''' element otherwise.

	==Cancelling==		==Cancelling==

Srslyyyy: Add note to sourceResource parameter.

2023-06-07T18:16:21Z

Add note to sourceResource parameter.

← Older revision		Revision as of 18:16, 7 June 2023
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	*'''source''': The [[event system#Event source\|source]] of this event is the [[element]] whose [[element data]] changed.		*'''source''': The [[event system#Event source\|source]] of this event is the [[element]] whose [[element data]] changed.
	*'''client''': The [[event system#Event client\|client]] global variable is set to the client that called [[setElementData]], or nil if it was called on the server.		*'''client''': The [[event system#Event client\|client]] global variable is set to the client that called [[setElementData]], or nil if it was called on the server.
	*'''sourceResource''': The [[resource]] which changed the element data. ~~(Only works in versions above 1.3.4-5937)~~		*'''sourceResource''': The [[resource]] which changed the element data - '''nil''' if client synced data, resource otherwise.

	==Cancelling==		==Cancelling==

MrTasty at 12:28, 8 October 2018

2018-10-08T12:28:32Z

← Older revision		Revision as of 12:28, 8 October 2018
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			{{Server event}}
	__NOTOC__		__NOTOC__
	~~{{Server event}}~~		This event is triggered ''after'' an element's [[element data\|data]] entry is changed. Such changes can be made on the client or the server using [[setElementData]].
	This event is triggered ~~when~~ an ~~elementdata~~ entry ~~for an element~~ changes~~. A client~~ can ~~perform this change~~ on the ~~element~~ or ~~it can be done~~ using [[setElementData]].

	==Parameters==		==Parameters==
	<syntaxhighlight lang="lua">		<syntaxhighlight lang="lua">
	string ~~theName~~, var ~~theOldValue~~		string theKey, var oldValue, var newValue
	</syntaxhighlight>		</syntaxhighlight>

	*'''~~theName~~''': The name of the element data entry that changed.		*'''theKey''': The name of the element data entry that has changed.
	*'''~~theOldValue~~''': The old value of this entry before it changed. ~~The~~ new value ~~can~~ be ~~accessed using~~ [[getElementData]] ( source, ~~theName~~ ).		*'''oldValue''': The old value of this entry before it changed. See [[element data]] for a list of possible datatypes.
			*'''newValue''': the new value of this entry after it changed. This will be equivalent to [[getElementData]](source, theKey).

	==Global parameters==		==Global parameters==
	*'''source''': The [[event system#Event source\|source]] of this event is the [[element]] whose element data changed		*'''source''': The [[event system#Event source\|source]] of this event is the [[element]] whose [[element data]] changed.
	*'''client''': The [[event system#Event client\|client]] global variable is set to the client that called [[setElementData]], or nil if it was called on the server.		*'''client''': The [[event system#Event client\|client]] global variable is set to the client that called [[setElementData]], or nil if it was called on the server.
	*'''sourceResource''': The [[resource]] which changed the element data. (Only works in versions above 1.3.4-5937)		*'''sourceResource''': The [[resource]] which changed the element data. (Only works in versions above 1.3.4-5937)
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	This example outputs a message to players when any of their element data values is changed.		This example outputs a message to players when any of their element data values is changed.
	<syntaxhighlight lang="lua">		<syntaxhighlight lang="lua">
	function outputChange(~~dataName~~, oldValue)		function outputChange(theKey, oldValue, newValue)
	if (getElementType(source) == "player") then -- check if the element is a player		if (getElementType(source) == "player") then -- check if the element is a player
	~~local newValue = getElementData(source, dataName) -- find the new value~~		outputChatBox("Your element data '" .. tostring(theKey) .. "' has changed from '" .. tostring(oldValue) .. "' to '" .. tostring(newValue) .. "'", source) -- output the change for the affected player
	outputChatBox("Your element data '" .. tostring(~~dataName~~) .. "' has changed from '" .. tostring(oldValue) .. "' to '" .. tostring(newValue) .. "'", source) -- output the change for the affected player		end
	end
	end		end
	addEventHandler("onElementDataChange", root, outputChange)		addEventHandler("onElementDataChange", root, outputChange)
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	This example checks and possibly reverses an element's data change.		This example checks and possibly reverses an element's data change.
	<syntaxhighlight lang="lua">		<syntaxhighlight lang="lua">
	function checkChange(~~dataName~~, oldValue)		function checkChange(theKey, oldValue)
	-- The client can only set 'special_thing' on its own player		-- The client can only set 'special_thing' on its own player
	if (~~dataName~~ == "special_thing") and (client ~= source) then		if (theKey== "special_thing") and (client ~= source) then
	outputChatBox("Illegal setting of " .. tostring(~~dataName~~) .. "' by '" .. tostring(getPlayerName(client)))		outputChatBox("Illegal setting of " .. tostring(theKey) .. "' by '" .. tostring(getPlayerName(client)))
	setElementData(source, ~~dataName~~, oldValue) -- Set back the original value		setElementData(source, theKey, oldValue) -- Set back the original value
	end		end
	end		end
	addEventHandler("onElementDataChange", root, checkChange)		addEventHandler("onElementDataChange", root, checkChange)

Botder at 02:56, 27 September 2018

2018-09-27T02:56:32Z

← Older revision		Revision as of 02:56, 27 September 2018
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	</section>		</section>

	==See ~~Also==~~		{{See also/Server event\|Element events}}
	~~===~~Element events~~===~~
	~~{{Element_events}}~~
	~~===Event functions===~~
	~~{{Event functions~~}}