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Bindable setter not called if value of property not changed?


Bindable setter not called if value of property not changed?

By : Ross
Date : November 16 2020, 06:23 AM
may help you . So digging around here a bit more I came across this question: Flex: Help me understand data Binding on getters and setters which describes the code generated by declaring a setter or getter Bindable
So apparently in the generated code there is a check to see if the value is different:
code :
public function set name(value:String)
{
    if (_name == value)
        return;
    _name = value;
    dispatchEvent(new Event("nameChanged"));
}


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Easiest way for a polymer-element to declare a bindable property with a getter/setter?

Easiest way for a polymer-element to declare a bindable property with a getter/setter?


By : Fabien
Date : March 29 2020, 07:55 AM
this will help Using an polymer-element's attributes attribute or publish block, it's very easy to create an attribute whose underlying storage is automatically managed. However, cases often come up where a property's value is not simply stored and retrieved. For example, a property's value may depend upon other element state. Another example: a property that's bindable but read-only. , A few points:
How to use Aurelia's bindable decorator on a property with getter and setter

How to use Aurelia's bindable decorator on a property with getter and setter


By : xEODGuy
Date : March 29 2020, 07:55 AM
hope this fix your issue Bindable works by adding a getter and a setter on your property that it uses for observing changes. It's recommended that you utilize the ${propertyName}Changed(newValue, oldValue) callback method to accomplish what you're trying to do. Here is an ES2016 example:
ViewModel
code :
import {bindable} from 'aurelia-framework';

export class MyCustomElement {
  @bindable name;

  _name;
  errorMessage = '';

  nameChanged(newValue) {
    if(newValue.length >= 5 ) {
      this.errorMessage = 'Name is too long';
    }
    else {
      this._name = newValue;
      this.errorMessage = '';
    }
  }
}
<template>
  <p>Name is: ${_name}</p>
  <p>Error is: ${errorMessage}</p>
</template>
Setter of bindable property never fires

Setter of bindable property never fires


By : Mustafa Aytekin
Date : March 29 2020, 07:55 AM
Hope this helps
But when I change it from the view model, it affects XAML view, but for some reasons doesn't call the setter for this property.
Creating bindable property with Xamarin C# gave No property, bindable property found

Creating bindable property with Xamarin C# gave No property, bindable property found


By : James Inflection
Date : March 29 2020, 07:55 AM
Hope this helps I created a class derived from StackLayout: , According to Xamarin docs, here is how to define a bindable property:
code :
public static readonly BindableProperty EventNameProperty =
BindableProperty.Create ("EventName", typeof(string),typeof(EventToCommandBehavior), null);
OnPropertyChanged is being called twice for a bindable property

OnPropertyChanged is being called twice for a bindable property


By : pierozek
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , We don't really have enough information to answer this question with certainty, but I can speculate.
Without seeing your SetValue method, my assumption would be that it lacks a short circuit, e.g. "don't do anything if the new value and the old value are the same".
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