added wxDataViewModel::HasContainerColumns

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@49136 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

docs/latex/wx/dataviewmodel.tex

@@ -147,6 +147,16 @@ of {\it item} or an invalid wxDataViewItem if {\it item} is the root item.
 Override this to indicate the value of {\it item}
 A \helpref{wxVariant}{wxvariant} is used to store the data.
 
+
+\membersection{wxDataViewModel::HasContainerColumns}\label{wxdataviewmodelhascontainercolumns}
+
+\constfunc{virtual bool}{HasContainerColumns}{\param{const wxDataViewItem\& }{item}}
+
+Override this method to indicate if a container item merely
+acts as a headline (or for categorisation) or if it also
+acts a normal item with entries for futher columns. By 
+default returns {\it false}.
+
 \membersection{wxDataViewModel::HasDefaultCompare}\label{wxdataviewmodelhasdefaultcompare}
 
 \constfunc{virtual bool}{HasDefaultCompare}{\void}

include/wx/dataview.h

@@ -142,6 +142,8 @@ public:
     // define hierachy
     virtual wxDataViewItem GetParent( const wxDataViewItem &item ) const = 0;
     virtual bool IsContainer( const wxDataViewItem &item ) const = 0;
+    // Is the container just a header or an item with all columns
+    virtual bool HasContainerColumns( const wxDataViewItem &item ) const { return false; }
     virtual unsigned int GetChildren( const wxDataViewItem &item, wxDataViewItemArray &children ) const = 0;
 
     // delegated notifiers