>I want to use a Treeview to display a list like Outlook Expresses  mail box.
>Each item is a file NOT a folder, but looks like a folder in the treeview.
>

If you merely want to represent a hierarchical list, you can simply add
nodes, otherwise you might want to add objects, ie nodes + data (eg you
might need the file data for each file you add to the node, so you use a
record to hold the data, then create a new instance and fill it every time
you you add an item).

  //Each TTreeView rebuild, get rid of any old stuff
  TV.items.Clear;

  //Add your root node
  rootNode := TV.items.Add(nil, nodeTitle);

  //Or add a root object
  rootNode := TV.items.AddObject(nil, nodeTitle, myRecord);
 

{-------------------------------------------------------------}

  //Add child nodes
  thisNode := TV.items.AddChild(refNode, nodeTitle);

  //Or add child objects
  thisNode := TV.items.AddChildObject(refNode, nodeTitle, myRecord);
 

{-------------------------------------------------------------}

//Let's have a simple record:

type
  pfData = ^fData;
  fileData = record
    fileSize: longInt;
    isDir: boolean;
  end;

{-------------------------------------------------------------}

  //Start the ball rolling by filling the root node
 

  pData.fileSize := 0;
  pData.isDir := true;
  rootNode := TV.items.AddObject(nil, 'Root directory', pData);
 

  //Then recurse through the directories:
  fillTree('C:\', rootNode);

{-------------------------------------------------------------}

unit recfiles;

interface
uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, ComCtrls;

type
  TForm1 = class(TForm)
    TV: TTreeView;
    mtree: TButton;
    procedure fillTree(currentDir: string; refNode: TTreeNode);
    procedure mtreeClick(Sender: TObject);
    procedure TVMouseDown(Sender: TObject; Button: TMouseButton;
      Shift: TShiftState; X, Y: Integer);
  private
    {Private declarations }
    rootNode: TTreeNode;
    expCol:   boolean;
  public
    {Public declarations }
  end;

type
  pfData = ^fileData;
  fileData = record
    fileSize: longInt;
    isDir: boolean;
  end;

var
  Form1: TForm1;
  SearchRec: TSearchRec;
  pData: pfData;

implementation

{$R *.DFM}

procedure TForm1.fillTree(currentDir: string; refNode: TTreeNode);
var
  thisNode: TTreeNode;
  res: longInt;
  sRec: TSearchRec;
begin
  res := FindFirst(currentDir + '*.*', faAnyFile, SearchRec);
  while res = 0 do
  begin
    new(pData);
    pData.fileSize := SearchRec.Size;
    pData.isDir := (SearchRec.Attr = faDirectory);

    if pData.isDir then
    begin

      //Exclude '.' and '..' directories from the recursion
      if (SearchRec.Name <> '.') and (SearchRec.Name <> '..') then
      begin
        thisNode := TV.items.AddChildObject(refNode, SearchRec.Name, pData);
        sRec := SearchRec;     //Save SearchRec till we return
        fillTree(currentDir + SearchRec.Name + '\', thisNode);
        SearchRec := sRec;     //and restore it
      end;
    end
    else
      TV.items.AddChildObject(refNode, SearchRec.Name, pData);
    res := FindNext(SearchRec);
  end;
end;

procedure TForm1.mtreeClick(Sender: TObject);
var
  currentTVD: pfData;
begin
  //Start the ball rolling by filling the root node
  SetCurrentDirectory('C:\');
  TV.items.Clear;
  new(pData);
  pData.fileSize := 0;
  pData.isDir := true;
  rootNode := TV.items.AddObject(nil, 'Root directory', pData);

  TV.Items.BeginUpdate;

  //Then recurse through the directories:
  fillTree('C:\', rootNode);         //Hardwired C:\
  rootNode.Expand(false);

  TV.Items.EndUpdate;

end;

procedure TForm1.TVMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
var
  MyHitTest : THitTests;
  currentTVD: pfData;
begin

  MyHitTest := TV.GetHitTestInfoAt(X,Y);   //Let's make sure we're on a label
  if htOnLabel in MyHitTest then           //
  begin
    currentTVD := pfData(TV.Selected.Data);
    if currentTVD.isDir then
      messageDlg(TV.Selected.Text + ' is a directory', mtInformation,
                                                    [mbOk], 0)
    else
      messageDlg('Size of file ' + TV.Selected.Text + ' is ' +
               IntToStr(currentTVD.fileSize), mtInformation, [mbOk], 0);
  end
  else
    expCol := false
end;

end.
 

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