samples/except/except.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        except.cpp
   3 // Purpose:     Except wxWindows sample
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     04/01/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 // ============================================================================
  13 // declarations
  14 // ============================================================================
  15
  16 // ----------------------------------------------------------------------------
  17 // headers
  18 // ----------------------------------------------------------------------------
  19
  20 // For compilers that support precompilation, includes "wx/wx.h".
  21 #include "wx/wxprec.h"
  22
  23 #ifdef __BORLANDC__
  24     #pragma hdrstop
  25 #endif
  26
  27 // for all others, include the necessary headers (this file is usually all you
  28 // need because it includes almost all "standard" wxWindows headers)
  29 #ifndef WX_PRECOMP
  30     #include "wx/app.h"
  31     #include "wx/frame.h"
  32     #include "wx/dialog.h"
  33
  34     #include "wx/button.h"
  35     #include "wx/sizer.h"
  36
  37     #include "wx/utils.h"               // for wxMessageBox
  38 #endif
  39
  40 // ----------------------------------------------------------------------------
  41 // resources
  42 // ----------------------------------------------------------------------------
  43
  44 // the application icon (under Windows and OS/2 it is in resources)
  45 #if defined(__WXGTK__) || defined(__WXMOTIF__) || defined(__WXMAC__) || defined(__WXMGL__) || defined(__WXX11__)
  46     #include "../sample.xpm"
  47 #endif
  48
  49 // ----------------------------------------------------------------------------
  50 // private classes
  51 // ----------------------------------------------------------------------------
  52
  53 // Define a new application type, each program should derive a class from wxApp
  54 class MyApp : public wxApp
  55 {
  56 public:
  57     // override base class virtuals
  58     // ----------------------------
  59
  60     // program startup
  61     virtual bool OnInit();
  62
  63     // 2nd-level exception handling: we get all the exceptions occuring in any
  64     // event handler here
  65     virtual void HandleEvent(wxEvtHandler *handler,
  66                              wxEventFunction func,
  67                              wxEvent& event) const;
  68
  69     // 3rd, and final, level exception handling: whenever an unhandled
  70     // exception is caught, this function is called
  71     virtual void OnUnhandledException();
  72 };
  73
  74 // Define a new frame type: this is going to be our main frame
  75 class MyFrame : public wxFrame
  76 {
  77 public:
  78     // ctor(s)
  79     MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size,
  80             long style = wxDEFAULT_FRAME_STYLE);
  81
  82     // event handlers (these functions should _not_ be virtual)
  83     void OnQuit(wxCommandEvent& event);
  84     void OnAbout(wxCommandEvent& event);
  85     void OnDialog(wxCommandEvent& event);
  86     void OnThrowString(wxCommandEvent& event);
  87
  88     // 1st-level exception handling: we overload ProcessEvent() to be able to
  89     // catch exceptions which occur in MyFrame methods here
  90     virtual bool ProcessEvent(wxEvent& event);
  91
  92 private:
  93     // any class wishing to process wxWindows events must use this macro
  94     DECLARE_EVENT_TABLE()
  95 };
  96
  97 // A simple dialog which has only some buttons to throw exceptions
  98 class MyDialog : public wxDialog
  99 {
 100 public:
 101     MyDialog(wxFrame *parent);
 102
 103     // event handlers
 104     void OnThrowInt(wxCommandEvent& event);
 105     void OnThrowObject(wxCommandEvent& event);
 106
 107 private:
 108     DECLARE_EVENT_TABLE()
 109 };
 110
 111 // A trivial exception class
 112 class MyException
 113 {
 114 public:
 115     MyException(const wxString& msg) : m_msg(msg) { }
 116
 117     const wxChar *what() const { return m_msg.c_str(); }
 118
 119 private:
 120     wxString m_msg;
 121 };
 122
 123 // ----------------------------------------------------------------------------
 124 // constants
 125 // ----------------------------------------------------------------------------
 126
 127 // IDs for the controls and the menu commands
 128 enum
 129 {
 130     // control ids
 131     Except_ThrowInt = 100,
 132     Except_ThrowObject,
 133
 134     // menu items
 135     Except_ThrowString = 200,
 136     Except_Dialog,
 137
 138     Except_Quit = wxID_EXIT,
 139     Except_About = wxID_ABOUT
 140 };
 141
 142 // ----------------------------------------------------------------------------
 143 // event tables and other macros for wxWindows
 144 // ----------------------------------------------------------------------------
 145
 146 // the event tables connect the wxWindows events with the functions (event
 147 // handlers) which process them. It can be also done at run-time, but for the
 148 // simple menu events like this the static method is much simpler.
 149 BEGIN_EVENT_TABLE(MyFrame, wxFrame)
 150     EVT_MENU(Except_Quit,  MyFrame::OnQuit)
 151     EVT_MENU(Except_About, MyFrame::OnAbout)
 152     EVT_MENU(Except_Dialog, MyFrame::OnDialog)
 153     EVT_MENU(Except_ThrowString, MyFrame::OnThrowString)
 154 END_EVENT_TABLE()
 155
 156 BEGIN_EVENT_TABLE(MyDialog, wxDialog)
 157     EVT_BUTTON(Except_ThrowInt, MyDialog::OnThrowInt)
 158     EVT_BUTTON(Except_ThrowObject, MyDialog::OnThrowObject)
 159 END_EVENT_TABLE()
 160
 161 // Create a new application object: this macro will allow wxWindows to create
 162 // the application object during program execution (it's better than using a
 163 // static object for many reasons) and also implements the accessor function
 164 // wxGetApp() which will return the reference of the right type (i.e. MyApp and
 165 // not wxApp)
 166 IMPLEMENT_APP(MyApp)
 167
 168 // ============================================================================
 169 // MyApp implementation
 170 // ============================================================================
 171
 172 // 'Main program' equivalent: the program execution "starts" here
 173 bool MyApp::OnInit()
 174 {
 175     // create the main application window
 176     MyFrame *frame = new MyFrame(_T("Except wxWindows App"),
 177                                  wxPoint(50, 50), wxSize(450, 340));
 178
 179     // and show it (the frames, unlike simple controls, are not shown when
 180     // created initially)
 181     frame->Show(true);
 182
 183     // success: wxApp::OnRun() will be called which will enter the main message
 184     // loop and the application will run. If we returned false here, the
 185     // application would exit immediately.
 186     return true;
 187 }
 188
 189 void
 190 MyApp::HandleEvent(wxEvtHandler *handler,
 191                    wxEventFunction func,
 192                    wxEvent& event) const
 193 {
 194     try
 195     {
 196         wxApp::HandleEvent(handler, func, event);
 197     }
 198     catch ( int i )
 199     {
 200         wxLogError(_T("Caught an int %d in MyApp."), i);
 201     }
 202 }
 203
 204 void MyApp::OnUnhandledException()
 205 {
 206     wxMessageBox(_T("Unhandled exception caught, program will terminate."),
 207                  _T("wxExcept Sample"), wxOK | wxICON_ERROR);
 208 }
 209
 210 // ============================================================================
 211 // MyFrame implementation
 212 // ============================================================================
 213
 214 // frame constructor
 215 MyFrame::MyFrame(const wxString& title, const wxPoint& pos, const wxSize& size, long style)
 216        : wxFrame(NULL, -1, title, pos, size, style)
 217 {
 218     // set the frame icon
 219     SetIcon(wxICON(mondrian));
 220
 221 #if wxUSE_MENUS
 222     // create a menu bar
 223     wxMenu *menuFile = new wxMenu;
 224     menuFile->Append(Except_Dialog, _T("Show &dialog\tCtrl-D"));
 225     menuFile->Append(Except_ThrowString, _T("Throw a &string\tCtrl-S"));
 226     menuFile->AppendSeparator();
 227     menuFile->Append(Except_Quit, _T("E&xit\tCtrl-Q"), _T("Quit this program"));
 228
 229     wxMenu *helpMenu = new wxMenu;
 230     helpMenu->Append(Except_About, _T("&About...\tF1"), _T("Show about dialog"));
 231
 232     // now append the freshly created menu to the menu bar...
 233     wxMenuBar *menuBar = new wxMenuBar();
 234     menuBar->Append(menuFile, _T("&File"));
 235     menuBar->Append(helpMenu, _T("&Help"));
 236
 237     // ... and attach this menu bar to the frame
 238     SetMenuBar(menuBar);
 239 #endif // wxUSE_MENUS
 240
 241 #if wxUSE_STATUSBAR && !defined(__WXWINCE__)
 242     // create a status bar just for fun (by default with 1 pane only)
 243     CreateStatusBar(2);
 244     SetStatusText(_T("Welcome to wxWindows!"));
 245 #endif // wxUSE_STATUSBAR
 246 }
 247
 248 bool MyFrame::ProcessEvent(wxEvent& event)
 249 {
 250     try
 251     {
 252         return wxFrame::ProcessEvent(event);
 253     }
 254     catch ( const wxChar *msg )
 255     {
 256         wxLogMessage(_T("Caught a string \"%s\" in MyFrame"), msg);
 257
 258         return true;
 259     }
 260 }
 261
 262 void MyFrame::OnQuit(wxCommandEvent& WXUNUSED(event))
 263 {
 264     // true is to force the frame to close
 265     Close(true);
 266 }
 267
 268 void MyFrame::OnDialog(wxCommandEvent& WXUNUSED(event))
 269 {
 270     MyDialog dlg(this);
 271
 272     dlg.ShowModal();
 273 }
 274
 275 void MyFrame::OnThrowString(wxCommandEvent& WXUNUSED(event))
 276 {
 277     throw _T("some string");
 278 }
 279
 280 void MyFrame::OnAbout(wxCommandEvent& WXUNUSED(event))
 281 {
 282     wxString msg;
 283     msg.Printf( _T("This is the About dialog of the except sample.\n")
 284                 _T("Welcome to %s"), wxVERSION_STRING);
 285
 286     wxMessageBox(msg, _T("About Except"), wxOK | wxICON_INFORMATION, this);
 287 }
 288
 289 // ============================================================================
 290 // MyDialog implementation
 291 // ============================================================================
 292
 293 MyDialog::MyDialog(wxFrame *parent)
 294         : wxDialog(parent, -1, wxString(_T("Throw exception dialog")))
 295 {
 296     wxSizer *sizerTop = new wxBoxSizer(wxVERTICAL);
 297
 298     sizerTop->Add(new wxButton(this, Except_ThrowInt, _T("Throw &int")),
 299                   0, wxCENTRE | wxALL, 5);
 300     sizerTop->Add(new wxButton(this, Except_ThrowObject, _T("Throw &object")),
 301                   0, wxCENTRE | wxALL, 5);
 302     sizerTop->Add(new wxButton(this, wxID_CANCEL, _T("&Cancel")),
 303                   0, wxCENTRE | wxALL, 5);
 304
 305     SetSizer(sizerTop);
 306     sizerTop->Fit(this);
 307 }
 308
 309 void MyDialog::OnThrowInt(wxCommandEvent& WXUNUSED(event))
 310 {
 311     throw 17;
 312 }
 313
 314 void MyDialog::OnThrowObject(wxCommandEvent& WXUNUSED(event))
 315 {
 316     throw MyException(_T("Exception thrown from the dialog"));
 317 }
 318