Add strike-through support to wxDataViewItem attributes

Implement support for this attribute only in the generic version so far,
it will hopefully be implemented for the natives ones in the future.

Also add a new toggle column to the dataview sample to check how it
works: checking the items in this column enables using this attribute
for some other ones.

Closes #18180.

samples/dataview/mymodels.h

@@ -9,6 +9,7 @@
 /////////////////////////////////////////////////////////////////////////////
 
 #include "wx/hashmap.h"
+#include <wx/vector.h>
 
 WX_DECLARE_HASH_MAP(unsigned, wxString, wxIntegerHash, wxIntegerEqual,
                     IntToStringMap);
@@ -196,6 +197,7 @@ class MyListModel: public wxDataViewVirtualListModel
 public:
     enum
     {
+        Col_Toggle,
         Col_EditableText,
         Col_IconText,
         Col_Date,
@@ -223,6 +225,9 @@ public:
 
     virtual wxString GetColumnType( unsigned int col ) const wxOVERRIDE
     {
+        if (col == Col_Toggle)
+            return wxT( "bool" );
+
         if (col == Col_IconText)
             return wxT("wxDataViewIconText");
 
@@ -237,6 +242,7 @@ public:
                                 unsigned int row, unsigned int col ) wxOVERRIDE;
 
 private:
+    wxVector<bool>   m_toggleColValues;
     wxArrayString    m_textColValues;
     wxArrayString    m_iconColValues;
     IntToStringMap   m_customColValues;