procedure Tf_treeview.Button1Click(Sender: TObject);
var MyTreeNode1 : TTreeNode;
begin
 with tv.Items do
  begin
    clear;
    q2.Close;
    //1.Hauptkategorie
    q2.SQL.Clear;
    q2.SQL.Add('select category_child_id from jos_vm_category_xref ');
    q2.SQL.Add('where category_parent_id = 0');
    q2.Open;

    //Liefert den Namen der Kategorie
    q1.Close;
    q1.SQL.Clear;
    q1.SQL.Add('select category_name from jos_vm_category ');
    q1.SQL.Add('where category_id = :category_id');
    q1.parambyname('category_id').AsInteger := q2.FieldByName('category_child_id').AsInteger;
    q1.Open;
    //----------------------------------------------------------------------------------------

    //Eintrag in Treeview
    MyTreeNode1 := Add(nil, q1.FieldByName('category_name').AsString);

    //Unterkategorien der ersten Hauptkategorie
    q3.Close;
    q3.SQL.Clear;
    q3.SQL.Add('select category_child_id from jos_vm_category_xref ');
    q3.SQL.Add('where category_parent_id = :category_parent_id');
    q3.ParamByName('category_parent_id').AsInteger := q2.FieldByName('category_child_id').AsInteger;
    q3.open;

    while not q3.eof do
     begin
      //Liefert den Namen der Kategorie
      q4.Close;
      q4.SQL.Clear;
      q4.SQL.Add('select category_name from jos_vm_category ');
      q4.SQL.Add('where category_id = :category_id');
      q4.parambyname('category_id').AsInteger := q3.FieldByName('category_child_id').AsInteger;
      q4.Open;

      //Eintrag der Unterkategorien in die TreeView
      AddChild(MyTreeNode1, q4.FieldByName('category_name').AsString);

      q3.Next;
     end;
    //--------------------------------
    q2.Next;

    //Liefert weitere Hauptkategorien und Unterkategorien
    while not q2.Eof do
     begin
      //Weitere Hauptkategorien in der TreeView anzeigen
      q1.Close;
      q1.SQL.Clear;
      q1.SQL.Add('select category_name from jos_vm_category ');
      q1.SQL.Add('where category_id = :category_id');
      q1.parambyname('category_id').AsInteger := q2.FieldByName('category_child_id').AsInteger;
      q1.Open;
      Add(MyTreeNode1, q1.FieldByName('category_name').AsString);
      //-------------------------------------------------------------
      //Unterkategorien der weiteren Hauptkategorien in Treeview anzeigen
      q3.Close;
      q3.SQL.Clear;
      q3.SQL.Add('select category_child_id from jos_vm_category_xref ');
      q3.SQL.Add('where category_parent_id = :category_parent_id');
      q3.ParamByName('category_parent_id').AsInteger := q2.FieldByName('category_child_id').AsInteger;
      q3.open;

      while not q3.eof do
       begin
        //Liefert den Namen der Kategorie
        q4.Close;
        q4.SQL.Clear;
        q4.SQL.Add('select category_name from jos_vm_category ');
        q4.SQL.Add('where category_id = :category_id');
        q4.parambyname('category_id').AsInteger := q3.FieldByName('category_child_id').AsInteger;
        q4.Open;
        //Eintrag der Unterkategorie in die TreeView
[COLOR="Red"]AddChild(MyTreeNode1, q4.FieldByName('category_name').AsString);[/COLOR]
        q3.Next;
       end;

      q2.Next;
     end;

  end;

end;