From c9f18835abd49fb620f371e0d956d25ab631aab0 Mon Sep 17 00:00:00 2001
From: Julian Smart <julian@anthemion.co.uk>
Date: Mon, 20 Feb 2012 11:38:52 +0000
Subject: [PATCH] Added wxEVT_WIZARD_BEFORE_PAGE_CHANGED event to allow the
 application to influence the return value of GetNext after Next is clicked.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70630 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
---
 include/wx/wizard.h    | 5 +++++
 interface/wx/wizard.h  | 8 ++++++++
 src/generic/wizard.cpp | 8 ++++++++
 3 files changed, 21 insertions(+)

diff --git a/include/wx/wizard.h b/include/wx/wizard.h
index 0c2453ca83..2d38be5b87 100644
--- a/include/wx/wizard.h
+++ b/include/wx/wizard.h
@@ -291,6 +291,7 @@ wxDECLARE_EXPORTED_EVENT( WXDLLIMPEXP_ADV, wxEVT_WIZARD_CANCEL, wxWizardEvent );
 wxDECLARE_EXPORTED_EVENT( WXDLLIMPEXP_ADV, wxEVT_WIZARD_HELP, wxWizardEvent );
 wxDECLARE_EXPORTED_EVENT( WXDLLIMPEXP_ADV, wxEVT_WIZARD_FINISHED, wxWizardEvent );
 wxDECLARE_EXPORTED_EVENT( WXDLLIMPEXP_ADV, wxEVT_WIZARD_PAGE_SHOWN, wxWizardEvent );
+wxDECLARE_EXPORTED_EVENT( WXDLLIMPEXP_ADV, wxEVT_WIZARD_BEFORE_PAGE_CHANGED, wxWizardEvent );
 
 typedef void (wxEvtHandler::*wxWizardEventFunction)(wxWizardEvent&);
 
@@ -307,6 +308,10 @@ typedef void (wxEvtHandler::*wxWizardEventFunction)(wxWizardEvent&);
 // changed - unless the event handler vetoes the event
 #define EVT_WIZARD_PAGE_CHANGING(id, fn) wx__DECLARE_WIZARDEVT(PAGE_CHANGING, id, fn)
 
+// Called before GetNext/GetPrev is called, so that the handler can change state that will be
+// used when GetNext/GetPrev is called. PAGE_CHANGING is called too late to influence GetNext/GetPrev.
+#define EVT_WIZARD_BEFORE_PAGE_CHANGED(id, fn) wx__DECLARE_WIZARDEVT(BEFORE_PAGE_CHANGED, id, fn)
+
 // the user pressed "Cancel" button and the wizard is going to be dismissed -
 // unless the event handler vetoes the event
 #define EVT_WIZARD_CANCEL(id, fn) wx__DECLARE_WIZARDEVT(CANCEL, id, fn)
diff --git a/interface/wx/wizard.h b/interface/wx/wizard.h
index 9244c18aca..de86f1a850 100644
--- a/interface/wx/wizard.h
+++ b/interface/wx/wizard.h
@@ -98,6 +98,10 @@ public:
         The page has been just changed (this event cannot be vetoed).
     @event{EVT_WIZARD_PAGE_CHANGING(id, func)}
         The page is being changed (this event can be vetoed).
+    @event{EVT_WIZARD_BEFORE_PAGE_CHANGED(id, func)}
+        Called after Next is clicked but before GetNext is called. Unlike EVT_WIZARD_CHANGING,
+        the handler for this function can change state that might affect the return value of
+        GetNext. This event can be vetoed.
     @event{EVT_WIZARD_PAGE_SHOWN(id, func)}
         The page was shown and laid out (this event cannot be vetoed).
     @event{EVT_WIZARD_CANCEL(id, func)}
@@ -231,6 +235,10 @@ public:
         The page has just been changed (this event cannot be vetoed).
     @event{EVT_WIZARD_PAGE_CHANGING(id, func)}
         The page is being changed (this event can be vetoed).
+    @event{EVT_WIZARD_BEFORE_PAGE_CHANGED(id, func)}
+        Called after Next is clicked but before GetNext is called. Unlike EVT_WIZARD_CHANGING,
+        the handler for this function can change state that might affect the return value of
+        GetNext. This event can be vetoed.
     @event{EVT_WIZARD_PAGE_SHOWN(id, func)}
         The page was shown and laid out (this event cannot be vetoed).
     @event{EVT_WIZARD_CANCEL(id, func)}
diff --git a/src/generic/wizard.cpp b/src/generic/wizard.cpp
index d8dbd11137..60d8fa754b 100644
--- a/src/generic/wizard.cpp
+++ b/src/generic/wizard.cpp
@@ -83,6 +83,7 @@ private:
 
 wxDEFINE_EVENT( wxEVT_WIZARD_PAGE_CHANGED, wxWizardEvent );
 wxDEFINE_EVENT( wxEVT_WIZARD_PAGE_CHANGING, wxWizardEvent );
+wxDEFINE_EVENT( wxEVT_WIZARD_BEFORE_PAGE_CHANGED, wxWizardEvent );
 wxDEFINE_EVENT( wxEVT_WIZARD_CANCEL, wxWizardEvent );
 wxDEFINE_EVENT( wxEVT_WIZARD_FINISHED, wxWizardEvent );
 wxDEFINE_EVENT( wxEVT_WIZARD_HELP, wxWizardEvent );
@@ -792,6 +793,13 @@ void wxWizard::OnBackOrNext(wxCommandEvent& event)
 
     bool forward = event.GetEventObject() == m_btnNext;
 
+    // Give the application a chance to set state which may influence GetNext()/GetPrev()
+    wxWizardEvent eventPreChanged(wxEVT_WIZARD_BEFORE_PAGE_CHANGED, GetId(), forward, m_page);
+    (void)m_page->GetEventHandler()->ProcessEvent(eventPreChanged);
+
+    if (!eventPreChanged.IsAllowed())
+        return;
+
     wxWizardPage *page;
     if ( forward )
     {
-- 
2.45.2