treeview naviagtion

simple use the onChange-Event of the TTreeView

meikl ;-)

This an abstract of a DB manager using a tree view.

unit Dict1;
interface
uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ComCtrls, ToolWin, StdCtrls, Buttons,db,DBTables,Printers, ImgList, Menus,
  ExtCtrls, DBCtrls, Mask,Login7b,UtilsG3, ActnList,AForStd3;

type
  TF1 = class(TForm)
    StatusBar1: TStatusBar;
    ...
    Tree1: TTreeView;
    ...
    procedure Tree1MouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
    procedure Tree1Click(Sender: TObject);
    procedure Tree1Collapsing(Sender: TObject; Node: TTreeNode;
      var AllowCollapse: Boolean);
    procedure Tree1Expanding(Sender: TObject; Node: TTreeNode;
      var AllowExpansion: Boolean);
    procedure Tree1KeyDown(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    procedure Tree1KeyUp(Sender: TObject; var Key: Word;
      Shift: TShiftState);
    ...
  end;

Useful function:
function GetNodeIndex(node: TTreeNode; mousecoord: TPoint): TTreeNode;

implementation

procedure TF1.Tree1MouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
var
  n: TTreeNode;
  tp: TPoint;
begin
tp.X := X;
tp.Y := Y;
n := GetNodeIndex((Sender as TTreeView).Items[0],tp);
if n = nil then
  n := (Sender as TTreeView).Selected
else
  (Sender as TTreeView).Selected := n;
if (n.Level = 1) and (not n.HasChildren) then
  DoWhatEverOnThisLevel(n.Level);
if Button = mbRight then begin
  Tree1click(Sender);
  PopMenu.Popup(X+(Sender as TTreeView).ClientOrigin.x,Y+(Sender as TTreeView).ClientOrigin.y);
  end;
end;

procedure TF1.Tree1Click(Sender: TObject);
var
  n: TTreeNode;
begin
if (Sender as TTreeView).Enabled = False then
  exit;
n := (Sender as TTreeView).Selected;
case n.Level of
  0: begin        // click on Root TreeItem
    DoAnythingForRootLevel(params);
    end;
  1: begin        // click on level 1
    end;
  ...
  end;

procedure TF1.Tree1Collapsing(Sender: TObject; Node: TTreeNode;
  var AllowCollapse: Boolean);
begin
// what to do when a node will be collapsed
if Node.Level = 0 then
  exit;
Tree1.Selected := Node;
end;

procedure TF1.Tree1Expanding(Sender: TObject; Node: TTreeNode;
  var AllowExpansion: Boolean);
begin
// what to do when a node will be expanded
if Node.Level = 0 then
  exit;
Tree1.Selected := Node;
end;

procedure TF1.Tree1KeyDown(Sender: TObject; var Key: Word;Shift: TShiftState);
var
  n: TTreeNode;
begin
if (Sender is TTreeView) and ((Sender as TTreeView).Focused) then begin
  n := (Sender as TTreeView).Selected;
  case  Key of
    VK_INSERT:
      InsertItem(n);
    VK_DELETE:
      DeleteItem(n);
    VK_RETURN: begin
      Tree1Click(Sender as TTreeView);
      end;
    end;
  end;
end;

procedure TF1.Tree1KeyUp(Sender: TObject; var Key: Word;Shift: TShiftState);
begin
if (Sender is TTreeView) and ((Sender as TTreeView).Focused) then begin
  if Key in [VK_PRIOR,VK_NEXT,VK_END,VK_HOME,VK_LEFT,VK_UP,VK_RIGHT,VK_DOWN] then
    Tree1Click((Sender as TTreeView));
  end;
end;

Enjoy.

Antonio.