don't use implicit wxString->char*/wchar_t* conversion, it will not be available in wxUSE_STL build in the future

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@46391 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/dcbase.cpp

@@ -2172,9 +2172,9 @@ void wxDCBase::GetMultiLineTextExtent(const wxString& text,
             heightTextTotal = 0, heightLineDefault = 0, heightLine = 0;
 
     wxString curLine;
-    for ( const wxChar *pc = text; ; pc++ )
+    for ( wxString::const_iterator pc = text.begin(); ; ++pc )
     {
-        if ( *pc == _T('\n') || *pc == _T('\0') )
+        if ( pc == text.end() || *pc == _T('\n') )
         {
             if ( curLine.empty() )
             {
@@ -2205,15 +2205,14 @@ void wxDCBase::GetMultiLineTextExtent(const wxString& text,
                 heightTextTotal += heightLine;
             }
 
-            if ( *pc == _T('\n') )
+            if ( pc == text.end() )
+            {
+               break;
+            }
+            else // '\n'
             {
                curLine.clear();
             }
-            else
-            {
-               // the end of string
-               break;
-            }
         }
         else
         {