Why is event PreUpdate and PostUpdate not triggered in ChartContainer?

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Jacob-Jan Sloots
Jacob-Jan Sloots 2025-12-12，13:59
回答： Aditya about 23 hours 前
Hi all,
I’ve created a ChartContainer in MATLAB R2024b and need to track when its update routine finishes so I can restore an internal property to its original value. During setup, I added listeners for the PreUpdate and PostUpdate events of the ChartContainer.
However, when I change a property, the update method runs, but neither the PreUpdate nor PostUpdate events seem to fire.
Below I share the class implementation:
classdef TestComponent < matlab.graphics.chartcontainer.ChartContainer
%% Properties
properties (AbortSet)
% Internal use. Indicates update is required, triggered by external
% property.
TriggerUpdate (1,1) logical = false;
end %properties
properties (Transient, NonCopyable, Hidden, SetAccess = protected, UsedInUpdate = false)
% Event listener array
EventListeners (1,:) event.listener
end
%% Protected Methods
methods (Access = protected)
function setup(obj)
% Setup routine
% Show setup routine is executed
disp('setup')
% Setup listeners to all events in the class
metaClass = meta.class.fromName(class(obj));
eventList = {metaClass.EventList.Name};
listenAcces = {metaClass.EventList.ListenAccess};
% Initialize listener to post-update event
for idx = 1:numel(eventList)
if ~strcmpi(listenAcces{idx}, {'public', 'protected'})
continue
end
obj.EventListeners(end+1) = listener(obj, ...
eventList{idx}, @(s,e) obj.showEvent(e));
end
end %function
function update(obj)
% Update routine
% Show update routine is executed
disp('update')
end %function
end %methods
methods
function showEvent(obj, e)
disp(e)
end %function
end %methods
end
Does anyone know why these events aren’t triggered? For ComponentContainer, the events work as expected.

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采纳的回答

Aditya
Aditya about 23 hours 前
Hi Jacob,
You have observed correctly: PreUpdate and PostUpdate events are available and documented for ComponentContainer (UI components), but not for ChartContainer (axes-based charts).Why aren't PreUpdate/PostUpdate firing in ChartContainer?
  • ChartContainer does not define or fire PreUpdate/PostUpdate events.
  • The MATLAB documentation for ComponentContainer explicitly lists these events, but the ChartContainer documentation does not.
  • This is by design: ChartContainer update cycle is not evented in the same way as ComponentContainer.
You can try the following steps:
  • Override the update method and place your logic before and after calling the superclass update, if needed.
  • If you need to execute code after every update, do it at the end of your update method.
  • If you have code that should run before an update, do it at the beginning of update.

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