Add the possibility to disable invisible wxDataViewCtrl items.

Add new wxDataViewModel::IsEnabled() and wxDataViewListStore::IsEnabledByRow()
methods and implement support for actually disabling the items in wxOSX/Cocoa
native implementation of wxDataViewCtrl and limited support for it in the
generic version.

We need to implement this in wxGTK using GtkCellRenderer "sensitive" propriety
later.

Closes #12686.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66403 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

samples/dataview/mymodels.cpp

@@ -244,6 +244,17 @@ bool MyMusicTreeModel::SetValue( const wxVariant &variant,
     return false;
 }
 
+bool MyMusicTreeModel::IsEnabled( const wxDataViewItem &item,
+                                  unsigned int col ) const
+{
+    wxASSERT(item.IsOk());
+
+    MyMusicTreeModelNode *node = (MyMusicTreeModelNode*) item.GetID();
+
+    // disable Beethoven's ratings, his pieces can only be good
+    return !(col == 3 && node->m_artist.EndsWith("Beethoven"));
+}
+
 wxDataViewItem MyMusicTreeModel::GetParent( const wxDataViewItem &item ) const
 {
     // the invisible root node has no parent
@@ -525,3 +536,14 @@ bool MyListModel::SetValueByRow( const wxVariant &variant,
 
     return false;
 }
+
+
+// ----------------------------------------------------------------------------
+// MyListStoreDerivedModel
+// ----------------------------------------------------------------------------
+
+bool MyListStoreDerivedModel::IsEnabledByRow(unsigned int row, unsigned int col) const
+{
+    // disabled the last two checkboxes
+    return !(col == 0 && 8 <= row && row <= 9);
+}