RE: [litwindow-users] Re: wxTextCtrl

[yrs90 <yr...@ya...>]

> I will investigate that. Might be a typo or it might be that for 
> wxTextCtrl SetValue and SetLabel do the same thing.

I found the following:

http://groups-beta.google.com/group/comp.soft-sys.wxwindows/browse_thread/th
read/c3e65abf426862e/06bfe1a5055f37a9

<quote>
I believe the correct API calls for working with the contents of a 
TextCtrl are GetValue and SetValue.  The fact that Get/SetLabel works 
on MSW is probably an artifact of how Windows itself implements the 
text controls.
</quote>



> > I'd like to assign a wxString to Value, but I'm having trouble 
> > figuring out
> > how to convert a wxString to an accessor in a wxTextCtrl rule.  I 
> > thought wrongly that perhaps the following rule would work.
> >
> > PROP_GetSet(wxString, Info)
> > RULE("xrcTextCtrl.Value",
> > make_accessor(make_expr<wxString>("xrcList.Current.Info")))
>
> I'll investigate.

Thanks.  I don't have a solution yet.

I've tried rules of a few different varieties:

RULE("xrcTextCtrl.Value", make_const<accessor>(make_accessor(wxString("test
string"))))

RULE("xrcTextCtrl.Value",
make_accessor(make_expr<wxString>("xrcList.Current.second.Info)))

RULE("xrcTextCtrl.Value", make_accessor(make_const<wxString>(wxString("test
string"))))

wxString test="test string";
BEGIN_RULES()
RULE("xrcTargetInfoMain.Value",
make_const<accessor>(make_accessor<wxString>(test)))
END_RULES()

The last case works.  The previous tries all fail.

The first case compiles but gives me a runtime error.  Oddly the crash is in
strlen().  It looks like the wxString hasn't been created yet.  Below is the
simplified-for-readability backtrace.

MSVCR80D!strlen+0x30
MSVCP80D!std::basic_string::assign+0x10
MSVCP80D!std::basic_string::basic_string
MyApp!litwindow::converter<wxString>::to_string+0x5d [base_objects.cpp @ 36]
MyApp!litwindow::converter<wxString>::to_string+0x4d [dataadapterimp.h @
736]
MyApp!litwindow::const_accessor::to_string
MyApp!litwindow::wxTextCtrlAdapter::SetValue
MyApp!litwindow::converter_with_getset<>::set_value
MyApp!litwindow::typed_accessor<>::set
MyApp!litwindow::value_assign_expr<>::do_assign
MyApp!litwindow::rule_base::execute_immediate
MyApp!litwindow::constraint_solver::execute_all_immediate
MyApp!litwindow::RapidUI::Start


Case 2 and 3, fail during compilation.  It complains about 'value_type' not
being a member of 'litwindow::accessor'.  I am guessing this isn't
interesting, but, if it is, I'll send the detailed errors.

Case 4 works.... Well that's some progress. However, I still don't see how
to dynamically lookup a wxString.  make_expr<wxString> returns
expr_primary<wxString> so it isn't suitable for changing into an
accessor<wxString>.


> > - - -
> >
> > On a different tact, I was puzzled by the following code snippet.
> Actually the code does invalidate multiple values here. It is a bit 
> difficult to see, because the 'Value' is an accessor itself.
> ...
> RapidUI rules dependency has two flavors. Static dependency means that a 
> rule depends on an accessor and that never changes its location and type 
> in memory during the lifetime of the rule. The object pointed to by this 
> accessor may change, but not the accessor itself.
> 
> Dynamic dependency otoh allows that the accessor itself changes.

This explanation is quite interesting.  So it follows that rules which pass
an accessor are always dynamic because it assigns a replacement accessor
each time the rule is updated?  What do static dependency rules look like?
(For a moment I thought make_expr<const_accessor> but that would just keep
the object pointed at from being changed, right?)

For the list assignment, the library takes care of invalidating the old
accessor so the user need not be concerned.  Are there times when the user
is required to call NotifyChanged on a value before updating?

Joel




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