added/documented wxWizard::HasNext/PrevPage()

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/branches/WX_2_4_BRANCH@17484 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/wizard.tex

@@ -160,6 +160,32 @@ Get the current page while the wizard is running. {\tt NULL} is returned if
 
 Returns the size available for the pages.
 
+\membersection{wxWizard::HasNextPage}\label{wxwizardhasnextpage}
+
+\func{virtual bool}{HasNextPage}{\param{wxWizardPage *}{page}}
+
+Return {\tt TRUE} if this page is not the last one in the wizard. The base
+class version implements this by calling 
+\helpref{page->GetNext}{wxwizardpagegetnext} but this could be undesirable if,
+for example, the pages are created on demand only.
+
+\wxheading{See also}
+
+\helpref{HasPrevPage}{wxwizardhasprevpage}
+
+\membersection{wxWizard::HasPrevPage}\label{wxwizardhasprevpage}
+
+\func{virtual bool}{HasPrevPage}{\param{wxWizardPage *}{page}}
+
+Return {\tt TRUE} if this page is not the last one in the wizard. The base
+class version implements this by calling 
+\helpref{page->GetPrev}{wxwizardpagegetprev} but this could be undesirable if,
+for example, the pages are created on demand only.
+
+\wxheading{See also}
+
+\helpref{HasNextPage}{wxwizardhasnextpage}
+
 \membersection{wxWizard::RunWizard}\label{wxwizardrunwizard}
 
 \func{bool}{RunWizard}{\param{wxWizardPage* }{firstPage}}

include/wx/wizard.h

@@ -201,6 +201,15 @@ public:
                             const wxPoint& pos = wxDefaultPosition,
                             const wxSize& size = wxDefaultSize);
 #endif // WXWIN_COMPATIBILITY_2_2
+
+    // the methods below may be overridden by the derived classes to provide
+    // custom logic for determining the pages order
+
+    virtual bool HasNextPage(wxWizardPage *page)
+        { return page->GetNext() != NULL; }
+
+    virtual bool HasPrevPage(wxWizardPage *page)
+        { return page->GetPrev() != NULL; }
 };
 
 // include the real class declaration

src/generic/wizard.cpp

@@ -348,7 +348,7 @@ bool wxWizard::ShowPage(wxWizardPage *page, bool goingForward)
 
         m_page->Hide();
 
-        btnLabelWasNext = m_page->GetNext() != (wxWizardPage *)NULL;
+        btnLabelWasNext = HasNextPage(m_page);
 
         // Get the bitmap of the previous page (if it exists)
         if ( m_page->GetBitmap().Ok() )
@@ -395,9 +395,9 @@ bool wxWizard::ShowPage(wxWizardPage *page, bool goingForward)
     }
 
     // and update the buttons state
-    m_btnPrev->Enable(m_page->GetPrev() != (wxWizardPage *)NULL);
+    m_btnPrev->Enable(HasPrevPage(m_page));
 
-    bool hasNext = m_page->GetNext() != (wxWizardPage *)NULL;
+    bool hasNext = HasNextPage(m_page);
     if ( btnLabelWasNext != hasNext )
     {
         // need to update