Use wxString's empty() when checking if the string is (non-)empty throughout wx.

Instead of constructs such as if "( s.length() )" and "if (s.length() > 0)" use "if ( !s.empty() )" instead. Similarly for "if (s.length() == 0)" or "if ( s.IsNull() )", use "if ( s.empty() )".
No code changes intended except for a few instances where a construct like "if ( s.length() && wxFileExists(s) )" was changed to not check the length of the string and let wxFileExists handle such cases.



git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66728 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/aui/auidemo.cpp

@@ -1548,7 +1548,7 @@ wxTextCtrl* MyFrame::CreateTextCtrl(const wxString& ctrl_text)
     static int n = 0;
 
     wxString text;
-    if (ctrl_text.Length() > 0)
+    if ( !ctrl_text.empty() )
         text = ctrl_text;
     else
         text.Printf(wxT("This is text box %d"), ++n);

samples/propgrid/propgrid.cpp

@@ -322,7 +322,7 @@ public:
         wxString s = ::wxGetSingleChoice(wxT("Message"),
                                          wxT("Caption"),
                                          m_choices.GetLabels());
-        if ( s.length() )
+        if ( !s.empty() )
         {
             SetValue(s);
             return true;

samples/propgrid/sampleprops.cpp

@@ -618,7 +618,7 @@ bool wxArrayDoubleProperty::StringToValue( wxVariant& variant, const wxString& t
 
     WX_PG_TOKENIZER1_BEGIN(text,delimiter)
 
-        if ( token.length() )
+        if ( !token.empty() )
         {
 
             // If token was invalid, exit the loop now

samples/widgets/bmpcombobox.cpp

@@ -884,7 +884,7 @@ wxBitmap BitmapComboBoxWidgetsPage::QueryBitmap(wxString* pStr)
 
     ::wxSetCursor( *wxHOURGLASS_CURSOR );
 
-    if ( filepath.length() )
+    if ( !filepath.empty() )
     {
         if ( pStr )
         {