I am currently adding data coming from CSV(Comma Separated Values) file.All the data from CSV is string only. As I have 35 rows and 6 Columns of data in string.
class ModelColumns : public Gtk::TreeModel::ColumnRecord
    {
        public:
        ModelColumns()
        {
               add(m_colA);
               add(m_colB);
               add(m_colC);
               add(m_colD);
               add(m_colE);
               add(m_colF);
        }
          Gtk::TreeModelColumn<Glib::ustring>             m_colA;
          Gtk::TreeModelColumn<Glib::ustring>             m_colB;
          Gtk::TreeModelColumn<Glib::ustring>             m_colC;
          Gtk::TreeModelColumn<Glib::ustring>             m_colD;
          Gtk::TreeModelColumn<Glib::ustring>             m_colE;
          Gtk::TreeModelColumn<Glib::ustring>             m_colF;
    };
    Gtk::FileChooserDialog dialog("Please select a file to open",
    Gtk::FILE_CHOOSER_ACTION_OPEN);
    dialog.set_transient_for(*this);
    //Add response buttons the the dialog:
    dialog.add_button("_Cancel", Gtk::RESPONSE_CANCEL);
    dialog.add_button("_Open", Gtk::RESPONSE_OK);
    //Add filters, so that only certain file types can be selected:
    auto filter_text = Gtk::FileFilter::create();
    filter_text->set_name("csv files (*.csv)|*.csv");
    filter_text->add_pattern("*");
    dialog.add_filter(filter_text);
    //Show the dialog and wait for a user response:
    int result = dialog.run();
     //Handle the response:
     switch(result)
     {
      case(Gtk::RESPONSE_OK):
      {
          std::string filename = dialog.get_filename();
          ifstream in(filename);
            string line, field;
            vector< vector<Glib::ustring> > array;  // the 2D array
            vector<Glib::ustring> v;         // array of values for one line only
            while ( getline(in,line) )   // get next line in file
            {
              v.clear();
              stringstream ss(line);
              while (getline(ss,field,','))  // break line into comma delimitted fields
              {
                v.push_back(field);  // add each field to the 1D array
              }
              array.push_back(v);  // add the 1D array to the 2D array
            }
       m_refTreeModel =  Gtk::ListStore::create(m_Columns);
       m_TreeView->set_model(m_refTreeModel);
       m_TreeView->append_column("Data1", m_Columns.m_colA);
       m_TreeView->append_column("Data2", m_Columns.m_colB);
       m_TreeView->append_column("Data3", m_Columns.m_colC);
       m_TreeView->append_column("Data4", m_Columns.m_colD);
       m_TreeView->append_column("Data5", m_Columns.m_colE);
       m_TreeView->append_column("Data6", m_Columns.m_colF);
       Gtk::TreeModel::Row row = *(m_refTreeModel->append());
       row[m_Columns.m_colA] = array[0][0]; row[m_Columns.m_colB] = array[0][1]; row[m_Columns.m_colC] = array[0][2];
       row[m_Columns.m_colD] = array[0][3]; row[m_Columns.m_colE] = array[0][4]; row[m_Columns.m_colF] = array[0][5];
       Gtk::TreeModel::Row row1 = *(m_refTreeModel->append());
       row1[m_Columns.m_colA] = array[1][0]; row1[m_Columns.m_colB] = array[1][1]; row1[m_Columns.m_colC] = array[1][2];            row1[m_Columns.m_colD] = array[1][3]; row1[m_Columns.m_colE] = array[1][4]; row1[m_Columns.m_colF] = array[1][5];
       //35 Rows Like This
       break;
      }
      default:
      {
       break;
      }
    }
Like this I am adding 35 rows. Its very Lengthy. I am getting data from string vector as I have added the code for FileChoser Function. I am defining a class for TreeModel as I added.
Deepak, India.
