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Bug 864 - ValueChanged event is not fired for UITextField
Summary: ValueChanged event is not fired for UITextField
Alias: None
Product: iOS
Classification: Xamarin
Component: Xamarin.iOS.dll (show other bugs)
Version: 4.x
Hardware: Macintosh Mac OS
: --- critical
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2011-09-16 15:31 UTC by Adrian Grigore
Modified: 2016-10-26 18:58 UTC (History)
4 users (show)

See Also:
Is this bug a regression?: ---
Last known good build:


Description Adrian Grigore 2011-09-16 15:31:32 UTC
The event "ValueChanged" is not fired on a UITextField when a charactor is
typed (or at all). 

(the Changed event IS fired in a UITextView, so I assume it's a typo?)

Steps to reproduce the problem:
1. Add a UITextField to a form. Wire it up
2. In MonoDevelop, attach to the field's ValueChanged event.
3. Put a breakpoint / logging in the valuechanged event code
4. watch it not fire the event as you type into the field

This bug seems identic to an old bug described at, but even though the bug is marked at RESOLVED, I was still able to reproduce it with version 4.0.7
Comment 1 Rolf Bjarne Kvinge 2011-09-21 07:48:58 UTC
The problem is that the native UITextField doesn't have (the native equivalent of) a Changed event, so there is nothing MonoTouch can hook up to.

There is however a notification you can observe (for the test project in the other bug report):

NSNotificationCenter.DefaultCenter.AddObserver (UITextField.TextFieldTextDidChangeNotification, (notification) =>
    Console.WriteLine ("Character received! {0}", notification.Object == TextField);

which will enable you to listen for when the text field's text changes.
Comment 2 Jiří Zoudun 2016-09-28 08:04:42 UTC
The cleanest way to observe UITextField changes is

_textField.AddTarget((sender, e) =>
    // Do your stuff in here
}, UIControlEvent.EditingChanged);

You don't have to subscribe to a system-wide notification center and you don't have to unregister observer when you're destroing a text field.
Comment 3 Flavius Demian 2016-10-26 18:58:36 UTC
The suggested fix with 

_textField.AddTarget((sender, e) =>
    // Do your stuff in here
}, does not work for me. 

Any other suggestions?

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