Leftover changes for sample doc improvements in ticket #9582 (most of the patch was...

[wxWidgets.git] / docs / doxygen / overviews / changes_since28.h

diff --git a/docs/doxygen/overviews/changes_since28.h b/docs/doxygen/overviews/changes_since28.h
index 73ea3787f113eff97b3701c3be2d0f79fb2f59ac..286671a76a86a4d463bfb99683ce2463c050de5d 100644 (file)
--- a/docs/doxygen/overviews/changes_since28.h
+++ b/docs/doxygen/overviews/changes_since28.h
@@ -109,5 +109,45 @@ Finally, a few structure fields, notable @c wxCmdLineEntryDesc::shortName,
   your code if you overrode these functions and change the functions in the
   derived classes to use const reference as well.
 
   your code if you overrode these functions and change the functions in the
   derived classes to use const reference as well.
 

+- Calling wxConfig::Write() with an enum value will fail to compile because
+  wxConfig now tries to convert all unknown types to wxString automatically
+  using wxToString() function.
+
+  The simplest solution is to cast the enum value to int, e.g.
+  @code
+    enum Colour { Red, Green, Blue };
+
+    wxConfig conf;
+    conf.Write("MyFavouriteColour", Red);       // ERROR: no match
+    conf.Write("MyFavouriteColour", int(Red));  // OK
+  @endcode
+
+  Another possibility which exists now is to provide an overload of
+  wxToString() (and wxFromString()) for your own type, e.g.
+
+  @code
+    wxString wxToString(Colour col)
+    {
+        return col == Red ? "R" : col == Green ? "G" : "B";
+    }
+
+    bool wxFromString(const wxString& s, Colour* col)
+    {
+        if ( s.length() != 1 )
+            return false;
+
+        switch ( s[0].GetValue() )
+        {
+            case 'R': *col = Red; return true;
+            case 'G': *col = Green; return true;
+            case 'B': *col = Blue; return true;
+        }
+
+        return false;
+    }
+  @endcode
+
+  Of course, this will change the format of the wxConfig output which may be
+  undesirable.

 */
 
 */