[Seaside] Newbie question

[James Foster]

Hi Adrian,

I haven't tried your code myself, but a brief visual scan suggests at  
least one problem that I've identified below...

On Aug 30, 2008, at 9:32 PM, r00t uk wrote:

> Hello All
>
> I am slowly working my way through Squeak and Seaside using "An  
> Introduction to Seaside" and the Seaside examples as my learning  
> guides.  I have come across an issue which I don't understand, and I  
> am hoping someone could enlighten me as to what is going wrong.  The  
> two methods below are called by  
> MLHeadDataModelView>>renderContentOn:,  with  
> MLHeadDataModelView>>renderCompanyTextInputOn: resulting in a  
> MessageNotUnderstood: WARenderCanvas>>value: error.
>
> The instance methods are:
>
> MLHeadDataModelView>>renderCompanyTextInputOn: "This method  
> generates the 'MessageNotUnderstood: WARenderCanvas>>value:' error"
> self
>         renderLabel: 'Company Name: '
>         input: [
>             html textInput;
>             value: self headDataModelView companyName;
>             callback: [:value | self headDataModelView companyName:  
> value]]
>         output: self headDataModelView companyName
>         on: html.
>
> MLHeadDataModelView>>renderEmployeeTextInputOn:
> self
>         renderLabel: 'Employee Name: '
>         input: [
>             html textInput setFocus;

In Smalltalk the semantics of a cascade (indicated by the semi-colon)  
means that the following #value: message is being sent to the receiver  
of the last message. The last message is #setFocus, and the receiver  
of the #setFocus was the object returned by the #textInput message.  
Thus, #value: is being sent to a WATextInputTag (or similar object),  
not to the WARenderCanvas (which is probably what you really wanted).

>             value: self headDataModelView employeeName;
>             callback: [:value | self headDataModelView employeeName:  
> value]]
>         output: self headDataModelView employeeName
>         on: html.
>
> MLHeadDataModelView>>initialize
> initialize
>     super initialize.
>    self headDataModelView: MLHeadDataModel new.
>
> I don't get any error messages if I use the on:of: style, but not  
> sure what exact difference or benefits are between the two.

The difference is that you don't have a #setFocus message.

> MLHeadDataModelView>>renderCompanyTextInputOn:
> renderCompanyTextInputOn: html
> self
>         renderLabel: 'Company Name: '
>         input: [
>             html textInput on: #companyName of: self  
> headDataModelView]
>         output: self headDataModelView companyName
>         on: html.
>
> MLHeadDataModelView>>renderEmployeeTextInputOn:
> renderEmployeeTextInputOn: html
> self
>         renderLabel: 'Employee Name: '
>         input: [
>             html textInput on: #employeeName of: self  
> headDataModelView]
>         output: self headDataModelView employeeName
>         on: html.
>
> Thanks in advance for any feedback.
>
> Regards
> Adrian

Hope that helps, and welcome to Seaside!

James Foster

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.squeakfoundation.org/pipermail/seaside/attachments/20080830/febc0a74/attachment-0001.htm