Creating a handler function with Bind to handle clicked menu item - wxWidgets 3.0

Question

I would like to know how to use Bind function to create a simple event handler in wxWidgets 3.0 , C++.

To start off my experimenting I have created a very simple application - a main frame with a menu and a couple of items in the menu. No problems so far, all appears as expected. A part of the code I used was :

//create a menu bar
wxMenuBar* mbar = new wxMenuBar();

wxMenu* fileMenu = new wxMenu(_T(""));

fileMenu->Append(item1, _("&Item_1"), _("Select item 1"));
mbar->Append(fileMenu, _("&File"));

Now I would like to create a simple handler using Bind, that would pop out a message box in the event of selecting Item_1 from the menu, for example :

wxMessageBox( "You have selected Item 1", "Your selection", wxOK | wxICON_INFORMATION );

Please note that the popping up of a message box was just a simple example I have chosen to quickly grasp the concept and see the result. If possible, I would like the Bind event handler to be as general as possible, for arbitrary events and actions.

Answer 1

#include <wx/wx.h>
#define item1 (wxID_HIGHEST + 1)

class CApp : public wxApp
{
public:
    bool OnInit() {
        // Create the main frame.
        wxFrame * frame = new wxFrame(NULL, wxID_ANY, "demo");
        // Create a menu bar.
        wxMenuBar* mbar = new wxMenuBar();
        wxMenu* fileMenu = new wxMenu(_T(""));
        fileMenu->Append(item1, _("&Item_1"), _("Select item 1"));
        mbar->Append(fileMenu, _("&File"));
        frame->SetMenuBar(mbar);
        // Bind an event handling method.
#if __cplusplus < 201103L
        frame->Bind(wxEVT_MENU, &CApp::item1_OnMenu, this, item1);
#else
        frame->Bind(wxEVT_MENU, [](wxCommandEvent & evt)->void{
            wxMessageBox("You have selected Item 1", "Your selection", wxOK | wxICON_INFORMATION);
        }, item1);
#endif
        // Enter the message loop.
        frame->Show(true);
        return this->wxApp::OnInit();
    }
#if __cplusplus < 201103L
protected:
    void item1_OnMenu(wxCommandEvent & evt) {
        wxMessageBox("You have selected Item 1", "Your selection", wxOK | wxICON_INFORMATION);
    }
#endif
};
DECLARE_APP(CApp)
IMPLEMENT_APP(CApp)

The method wxEvtHandler::Bind has 3 overloads. The above only demonstrates 2 of them.

For the available event types, which will be the 1st param of Bind, please refer to wx/event.h. The event.h also tells us which event class should be used. For example,

#define EVT_MENU(winid, func) wx__DECLARE_EVT1(wxEVT_MENU, winid, wxCommandEventHandler(func))

note the wxCommandEventHandler, remove the suffix Handler and the remaining will be the event class wxCommandEvent.