CheckboxInputElement.onChange event not triggered
Question
My code is simple but the line print("checky changed") is not run. It should be run because after registering the onChange listener, which should print a message when the checked status of the checkbox is changed, I change the checked status of the checkbox two times: first directly, then in a Timer executed three seconds later, every time with different values.
If I manually check or uncheck the checkbox, the message is printed.
I really need help with this problem: why the message "checky changed" is never printed when checky.checked 's value is changed programmatically?
I have this HTML code:
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>Test</title>
<script async type="application/dart" src="script.dart"></script>
<script async src="packages/browser/dart.js"></script>
</head>
<body>
<h1>Test</h1>
<input type="checkbox" id="checky">
</body>
</html>
and this Dart code:
import 'dart:html';
import 'dart:async';
void main() {
CheckboxInputElement checky = querySelector('#checky');
checky..checked = true
..onChange.listen((_) {
print("checky changed");
});
checky.checked = false;
new Timer(const Duration(seconds: 3), () {
checky.checked = true;
});
}
Thank you very much for any kind of help!
2 answers
solution1
2 2014-07-25 22:26:04
The forms option onchange doesn't fire programmatically. You need to execute the on change method after alter the checked property. Seb
solution2
2 2014-07-26 00:19:48
You can dispatch onChange event manually:
import 'dart:html';
import 'dart:async';
void main() {
CheckboxInputElement checky = querySelector('#checky');
checky
..checked = true
..onChange.listen((_) {
print("checky changed");
});
new Timer(const Duration(seconds: 1), () {
checky.dispatchEvent(new Event("change"));
checky.checked = !checky.checked;
});
}
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