Extending wxCommandEvent

[Eran Ifrah]

Hi,

I often use wxCommandEvent to pass around commands from one handler to another

One of the pains I am having is to keep track of the wxClientData I am setting in the event (i.e. delete it when its no longer needed)

I ended up writing a small class like this:

class WXDLLIMPEXP_CL clCommandEvent : public wxCommandEvent

{

    wxSharedPtr<wxClientData> m_ptr;

public:

    clCommandEvent(wxEventType commandType = wxEVT_NULL, int winid = 0);

    clCommandEvent(const clCommandEvent& event);

    virtual ~clCommandEvent();

    // Hides wxCommandEvent::Set{Get}ClientObject

    void SetClientObject(wxClientData* clientObject) ;

    wxClientData *GetClientObject() const ;

    virtual wxEvent *Clone() const;

};

typedef void (wxEvtHandler::*clCommandEventFunction)(clCommandEvent&);

#define clCommandEventHandler(func) \

    wxEVENT_HANDLER_CAST(clCommandEventFunction, func)

Basically it hides wxCommandEvent 'Set{Get}ClientObject' by setting the wxClientData passed by the user to an internal wxSharedPtr<wxClientData> member

This allows my clCommandEvent class to take ownership on the user's clientObject and delete it when its no longer referenced

This seems a very useful to me and I wondered whether you consider extending wxCommandEvent with new API something like (using 'Assign' to be consistent with other APIs):

AssignClientObject / GetAssignedClientObject 

--

 

Eran Ifrah
Author of codelite, a cross platform open source C/C++ IDE: http://www.codelite.org

wxCrafter, a wxWidgets RAD: http://wxcrafter.codelite.org

[Vadim Zeitlin]

On Tue, 21 May 2013 00:14:01 +0300 Eran Ifrah wrote:

EI> I often use wxCommandEvent to pass around commands from one handler to
EI> another One of the pains I am having is to keep track of the
EI> wxClientData I am setting in the event (i.e. delete it when its no
EI> longer needed)

I think this is a rather unusual situation. The client data is supposed to
be owned by a control, not event.

EI> I ended up writing a small class like this:

Of course, if you do want to have client data in your events, your
approach works just fine.

EI> This seems a very useful to me and I wondered whether you consider
EI> extending wxCommandEvent with new API something like (using 'Assign' to be
EI> consistent with other APIs):
EI>
EI> AssignClientObject / GetAssignedClientObject

No, I don't think this is useful enough to be done in wxCommandEvent. I'm
also a bit suspicious of the whole idea, it doesn't seem right to me to
have objects owned by the events even if I can't give any concrete reason
as to why would it be so right now. So I'd prefer to not change anything in
wxCommandEvent.

Regards,
VZ

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