Re: [gtkmm] TreeModelColumn associated with a TreeViewColumn ?

[Liza Klerck <liza trdlnk com>]

Daniel Elstner wrote:
> On Fre, 2003-01-10 at 00:22, Jarek Dukat wrote:
> > On Thu, 2003-01-09 at 22:38, Liza Klerck wrote:
> > > How do I retrieve the Gtk::TreeViewColumn associated with a 
> > > Gtk::TreeModelColumn after the TreeViewColumn has already been created ?
> > >       
> > Liza, have you tried looking at Gtkmm TreeView docs? It is all there...
> > http://gtkmm.sourceforge.net/gtkmm2/docs/reference/html/classGtk_1_1TreeView.html
> >
> > TreeViewColumn* TreeView::get_column (int n);
> > CellRenderer* TreeView::get_column_cell_renderer (int n);
> > Glib::ListHandle<TreeViewColumn*> TreeView::get_columns ();
> > And const versions of these methods of course.
> >       
>
> Well, that's actually not what she wants.  The int n denotes the view
> column index, not the model column index.
>
> Liza, I think it's a bad idea to try to retrieve the view column from
> the model column.  It breaks the model/view separation, and I can't
> imagine a situation where it might be useful.  Could you tell us what
> your code is about?  That would help to find an appropriate way to do
> it.
>
> --Daniel
>
>
>       
Ok here is an example of why I need to know which Gtk::TreeModelColumn is
accociated with a specific Gtk::TreeViewColumn: 
      
   Let's say I have a treeview with 3 columns column_a, column_b and column_c; 
      
   I register for button_press_events in the TreeView so that when a user
 presses the mouse button in the column_b I want to call function do_column_b(row)
      
   when he clicks in column_c I want to call function do_column_c(row)  
      
  void do_column_b(Gtk::TreeModel::Row &row)
  {   .....   }
      
  void do_column_c(Gtk::TreeModel::Row &row)
   {   .....  }
      
class ModelColumns : public Gtk::TreeModel::ColumnRecord 
  { 
  public: 
   ModelColumns()  {   add(m_col_a); add(m_col_b);     add(m_col_c);   add(m_col_visible); 
} 
   Gtk::TreeModelColumn<string> m_col_a; 
   Gtk::TreeModelColumn<double> m_col_b; 
   Gtk::TreeModelColumn<double> m_col_c; 
   Gtk::TreeModelColumn<bool> m_col_visible;    }; 
      
  ModelColumns m_Columns; 
  Gtk::TreeView m_TreeView; 
  Glib::RefPtr<Gtk::TreeStore> m_refTreeModel; 
      
  m_refTreeModel = Gtk::TreeStore::create(m_Columns); 
  m_TreeView.set_model(m_refTreeModel); 
      
  // Append the column 
  m_TreeView.append_column("A", m_Columns.m_col_a); 
  m_TreeView.append_column("B", m_Columns.m_col_b); 
  m_TreeView.append_column("C", m_Columns.m_col_c); 
      
  // I register to receive a callback for button press events in the treeview. 
      
  m_TreeView.add_events(Gdk::BUTTON_PRESS_MASK); 
  m_TreeView.signal_button_press_event().connect(  SigC::slot(*this,  &ExampleWindow::on_m_TreeView_button_press),
false ); 
      
  bool  ExampleWindow::on_m_TreeView_button_press(GdkEventButton *eventbutton) 
      
  { 
   Gtk::TreeModel::Path  path; 
   Gtk::TreeViewColumn*  column; 
   int cell_x; 
   int cell_y; 
    Gtk::TreeModel::Row row;
      
   // catch mouse button1 clicks 
   switch (eventbutton->type) 
   { 
       case GDK_BUTTON_PRESS: 
       if ( eventbutton->button == 1) 
         { 
           if (m_TreeView.get_path_at_pos(eventbutton->x,  eventbutton->y, 
path, column, cell_x, cell_y )) 
           {   
              // Get the row number
              int row_num = *path.get_indices().begin();               
              row = *( m_refTreeModel->children[row_num - 1]);    
      
              // Get the column number
              int column_number = -1; 
              while (column != treeView->get_column(column_number)) 
              column_number)++; 
            } 
      
            // So at this point I have a Gtk::TreeViewColumn, and a column
number  and a row and a row number but programatically I still don't know
      
            // if the user clicked on [column b] or [column c]  
            // Thus I need to know which Gtk::TreeModelColumn was  accociated
with column  at creation time 
            //  So something like this where "Column B" and "Column C" is
the part I need 
            if (column == "Column B") 
            { 
                do_function_b(row); 
            } 
            if (column == "Column C") 
             { 
                 do_function_c(row); 
             } 
        } 
    return false; 
  } 
      
  I hope this example explains better what I am trying to do - I am still
pretty new at Gtk2.
  Thanks !
  Liza