[Gambas-user] Calling a sub from a Webview

[Tobias Boege]

On Wed, 04 Dec 2013, Jesus wrote:
> El 04/12/13 22:32, Tobias Boege escribi?:
> > On Wed, 04 Dec 2013, Jesus wrote:
> >> Hi all
> >>
> >> I currently helping to port a VB6 program to Gambas3, but to my
> >> surprise, it does weird things like these from the post title: it is
> >> calling methods and functions from the html code inside a webbrowser
> >> control.
> >>
> >> It has a wb control that acts like a sort of wizard/help thing, and the
> >> html links in that view are calling methods inside the application. That
> >> links are as '<a href="act:some_class.method">some action</a>'
> >>
> >> So the question is, could it be done with gambas somehow?
> >>
> >> Regards
> >> --
> >> Jesus Guardon
> >
> > Jesus (meant as an interjection)! I know I shouldn't question other people's
> > design choices but this is just mad. Actually it might have seemed like an
> > elegant way to communicate with an HTML page to the original author of that
> > program - I understand that - but this is just asking for trouble, IMHO.
> >
> > However, I guess Object.Call() is your best bet here.
> >
> > Regards,
> > Tobi
> >
> 
> Hi Tobi, thanks for reply
> 
> I am at your side about some (mad) practices, but...
> 
> I think Object.Call is suitable for calling or executing code inside or 
> outside of the current class, but not the other way round, IIUC. How 
> could I execute Object.Call from inside a webview? None of the events 
> webview exposes are suitable for doing this IMO, since the webview.url 
> is a property, not a method.
> 
> I will experiment, thanks for the tip!
> 

Ahh, I got you wrong apparently... My answer can be applied if you have any
occasion (event) to parse an (X)HTML element for this special attribute
href="act:some_class.method". Then you can extract the class and method name
and use Object.Call().

You can (ab)use the WebView's Click event like this: Modify the <a> element
to look like this:

<a href="#act:some_class.method">some action</a>

Then, when clicked, the WebView will load the valid URL (the anchor sign had
to be prepended to make it valid - to trigger the Click event, in turn) and
provide you a WebFrame object in whose Url property you have the wanted
act:some_class.method string somewhere. Now parse and execute.

I think it's too late for me to find clear words, so I attach a minimal
example. (Note that the code is executed twice in this project which is
certainly not desirable. You'll sure find a way to prevent this yourself.)

Regards,
Tobi
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