ValueChanged event not fired on uieditfield when setting property Value

31 次查看（过去 30 天）

显示更早的评论

Andreas Klotzek 2019-1-10

1
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/439147-valuechanged-event-not-fired-on-uieditfield-when-setting-property-value

评论： Rob Campbell 2022-12-22

在 MATLAB Online 中打开

I have a uieditfield:

u = uieditfield();

The I attach a listener to the ValueChangedFcn

u.ValueChangedFcn = @(s,e)disp(e);

If I type into the edit field the my listener gets called as expected. But if I set the property directly

u.Value = '2';

no event is fired.

Is there something wrong with what I am doing or with Matlab?

5 个评论
显示 3更早的评论隐藏 3更早的评论

J. Alex Lee 2020-4-24

Is this a concious decision based on some programming principle? It seems to me the more obvious/expected behavior is that changing the "Value", no matter how, triggers the "ValueChangedFcn"...otherwise they should have called it the "UIElementManipulatedFcn"...

I understand the wrapper concept as suggested by Adam and demonstrated by Jan, but it seems a cumbersome solution especially if you want to ensure your event object looks the same as it does from the manipulation of the ui element, and you want to do this for many types of ui elements...

Am I missing something?

Rob Campbell 2022-12-22

I agree. This is weird and differs from how this works in a Figure vs a UI.

请先登录，再进行评论。

请先登录，再回答此问题。

回答（2 个）

Jan 2019-1-11

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/439147-valuechanged-event-not-fired-on-uieditfield-when-setting-property-value#answer_355980

编辑：Jan 2019-1-11

在 MATLAB Online 中打开

You can write a wrapper for setting the value programmatically, which calls the callback manually:

function SetMyValue(objectH, Value)
objectH.Value = Value;
myEvent.Origin = 'Value set programmatically';
objectH.ValueChangedFcn(objectH, myEvent);
end

9 个评论
显示 7更早的评论隐藏 7更早的评论

shakedpa 2022-10-7

@Jan I discovered this issue today, so I honestly ask what is the "intended" way to solve my needs:

I have a set of multiple toggle switches, they represent a state of the system (the fact that they are switches and not something else doesn't really matter, but I do need an actual GUI component and not some hidden state variable, because the users are expected to use some of the switches).

Because I don't want the users to have to set the full state every time, I added a "load settings" button, which loads a .mat file with a system-state variable, and assigns the correct values to all the switches.

Now, when the load button's callbak function set the correct values to the system-state switches, this doesn't fire their corresponding value-changed-callback-functions. I undrstand your comment that this is not the intended way to write this type of code, so I ask - how should I do it differently? (Instead of using one of the bypasses suggested here)

Specifically, how can I interact with multiple GUI components with one action, while still preserving their individual functionality?

Walter Roberson 2022-10-8

@Nathaniel Allan-Rahill

"however, it doesn't prevent an unaware user from programmatically changing a UI component property value without an appropriate set/callback method being executed"

A "user" who has access to **programmatically* change the ui component property values is a developer, so you are effectively asking how one developer can prevent a different developer from taking particular actions with the class that the second developer has source-code-modification access to.

If you want to divide an application into two parts, one modifiable by original developers and the second modifiable by less knowledgeable secondary developers, then put access restrictions on properties so that the secondary developers have to go through an interface to set the properties and the interface ensures that the necessary steps are taken to ensure consistency.

shakedpa 2022-10-10

The original suggestion by Jan works fine, so that's ok for me. I felt there was a "more correct" way of doing it, but if there isn't anything obvious - nevermind.

请先登录，再进行评论。

Alexander Cranney 2021-11-15

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/439147-valuechanged-event-not-fired-on-uieditfield-when-setting-property-value#answer_832069

编辑：Alexander Cranney 2021-11-15

在 MATLAB Online 中打开

Another way to get the behavior you want is (mis)use a test case. Test cases have a number of methods for modifying GUI values in ways that mimic having a user manipulate the values, which fires all of the ChangedFcns. In this case, you can use the "type" method:

https://www.mathworks.com/help/matlab/ref/matlab.uitest.testcase.type.html

u = uieditfield();
u.ValueChangedFcn = @(s,e)disp(e);
fakeTestCase = matlab.uitest.TestCase.forInteractiveUse;
fakeTestCase.type(u,'2')

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Alexander Cranney 2021-11-15

在 MATLAB Online 中打开

Ah, looks like you can do it in a single line without instantiating "fakeTestCase":

matlab.uitest.TestCase.forInteractiveUse.type(u,'2');

请先登录，再进行评论。

请先登录，再回答此问题。

类别

MATLAB Graphics Graphics Objects Interactive Control and Callbacks

在 Help Center 和 File Exchange 中查找有关 Interactive Control and Callbacks 的更多信息

产品

MATLAB

版本

R2018b

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by