Re: Handling ui feedback loops

> > Whats the proper pattern for this use of tweak fields and input  
> fields?
>
> You'll have to guard manually, e.g., instead of either
>
> MyInputField>>onModelValueChanged
>     <on: valueChanged in: model>
>     self value := model value asString.
>
> MyInputField>>onValueChanged
>     <on: valueChanged>
>     model value := Number readFrom: self value.
>
> (which may loop) use either one of:
>
> MyInputField>>onModelValueChanged
>     <on: valueChanged in: model>
>     newValue := model value asString.
>     newValue = value ifFalse:[
>         self value := newValue.
>     ].
>
> MyInputField>>onValueChanged
>     <on: valueChanged>
>     newValue := Number readFrom: self value.
>     newValue = model value ifFalse:[
>         model value := newValue.
>     ].
>
> Cheers,
>   - Andreas
>
> Steven W. Riggins wrote:
>> I have a input field and when I change the value of the tweak  
>> field, its mirrored into the field.  I also use this field as a  
>> input field, so I want to know when the value changed, and update  
>> my model.  Problem is, I set the field, I get a changed event, I  
>> convert the field string gto a number, set my model, which updates  
>> the field, and around and around I go.
>> propertyValueAt: key put: newValue with: changeEvent
>>     "Store the value of my property at key"
>>     | oldValue |
>>     myProperties ifNil:[myProperties := IdentityDictionary new].
>>     oldValue := myProperties atProperty: key put: newValue.
>>     oldValue == newValue ifTrue:[^newValue].
>>     self signalChanged: changeEvent from: oldValue to: newValue.
>>     ^newValue
>> Does ==, which fails because '123' == (123 asString) fails.
>> WHats the proper pattern for this use of tweak fields and input  
>> fields?
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