object Form1: TForm1
  Left = 325
  Top = 82
  Width = 651
  Height = 599
  Caption = 'Registry Lookup Thread Test'
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'MS Sans Serif'
  Font.Style = []
  OldCreateOrder = False
  OnCreate = FormCreate
  PixelsPerInch = 96
  TextHeight = 13
  object HKCRMemo: TMemo
    Left = 0
    Top = 0
    Width = 321
    Height = 186
    Lines.Strings = (
      'HKCRMemo')
    ReadOnly = True
    ScrollBars = ssBoth
    TabOrder = 0
    WordWrap = False
  end
  object HKCUMemo: TMemo
    Left = 320
    Top = 0
    Width = 321
    Height = 186
    Lines.Strings = (
      'HKCUMemo')
    ReadOnly = True
    ScrollBars = ssBoth
    TabOrder = 1
    WordWrap = False
  end
  object HKLMMemo: TMemo
    Left = 0
    Top = 185
    Width = 321
    Height = 186
    Lines.Strings = (
      'HKLMMemo')
    ReadOnly = True
    ScrollBars = ssBoth
    TabOrder = 2
    WordWrap = False
  end
  object HKUMemo: TMemo
    Left = 320
    Top = 185
    Width = 321
    Height = 186
    Lines.Strings = (
      'HKUMemo')
    ReadOnly = True
    ScrollBars = ssBoth
    TabOrder = 3
    WordWrap = False
  end
  object HKCCMemo: TMemo
    Left = 0
    Top = 375
    Width = 321
    Height = 186
    Lines.Strings = (
      'HKCCMemo')
    ReadOnly = True
    ScrollBars = ssBoth
    TabOrder = 4
    WordWrap = False
  end
  object Button1: TButton
    Left = 325
    Top = 375
    Width = 316
    Height = 161
    Caption = 'Do Test'
    TabOrder = 5
    OnClick = Button1Click
  end
  object StaticText1: TStaticText
    Left = 325
    Top = 540
    Width = 311
    Height = 17
    Alignment = taCenter
    AutoSize = False
    BevelInner = bvNone
    BevelKind = bkTile
    BorderStyle = sbsSingle
    Caption = 'Total Time : N/A'
    TabOrder = 6
  end
  object Timer1: TTimer
    OnTimer = Timer1Timer
    Left = 390
    Top = 530
  end
end

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Registry, ExtCtrls;

type
  TRegistryThread = class(TThread)
  private
    procedure RegistrySearch(KeyName: String);
  protected
    procedure Execute; override;
  public
    RegistryHKey : HKEY;
    Memo : TMemo;
  end;

type
  TForm1 = class(TForm)
    HKCRMemo: TMemo;
    HKCUMemo: TMemo;
    HKLMMemo: TMemo;
    HKUMemo: TMemo;
    HKCCMemo: TMemo;
    Button1: TButton;
    StaticText1: TStaticText;
    Timer1: TTimer;
    procedure Button1Click(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    function RunThread(RegistryHKey: HKEY; Memo: TMemo): TRegistryThread;
    procedure ThreadTerminated(Sender: TObject);
  public
    rtHKCR, rtHKCU, rtHKLM, rtHKU, rtHKCC : TRegistryThread;
  end;

var
  Form1 : TForm1;
  TotalDone : Integer = 0;
  TotalSeconds : Integer = 0;

implementation

{$R *.dfm}

procedure TRegistryThread.RegistrySearch(KeyName: String);
var
  Reg : TRegistry;
  Names : TStringList;
  Delimiter : String;
  I : Integer;
begin
  Reg := TRegistry.Create;
  Names := TStringList.Create;
  Reg.RootKey := RegistryHKey;
  Try
    If Reg.OpenKeyReadOnly(KeyName) Then
      begin
      If Reg.HasSubKeys Then
        begin
        Reg.GetKeyNames(Names);
        For I := 0 To Names.Count - 1 Do
          begin
          Memo.Lines.Add(KeyName + '\' + Names.Strings[I]);
          SendMessage(Memo.Handle, EM_SCROLLCARET, 0, 0);
          RegistrySearch(KeyName + '\' + Names.Strings[I]);
        end;
      end;
    end;
  finally
    Reg.Free;
    Names.Free;
  end;
end;

procedure TRegistryThread.Execute;
var
  Reg : TRegistry;
  Names : TStringList;
  Delimiter : String;
  I : Integer;
begin
  inherited;
  Reg := TRegistry.Create;
  Names := TStringList.Create;
  Reg.RootKey := RegistryHKey;
  Try
    If Reg.OpenKeyReadOnly('\') Then
      begin
      Reg.GetKeyNames(Names);
      For I := 0 To Names.Count - 1 Do
        begin
        Memo.Lines.Add('\' + Names.Strings[I]);
        RegistrySearch('\' + Names.Strings[I]);
      end;
    end;
  finally
    Reg.Free;
    Names.Free;
  end;
end;

procedure TForm1.ThreadTerminated(Sender: TObject);
begin
  Inc(TotalDone);
end;

function TForm1.RunThread(RegistryHKey: HKEY; Memo: TMemo): TRegistryThread;
var
  RegistryThread : TRegistryThread;
begin
  RegistryThread := TRegistryThread.Create(True);
  RegistryThread.FreeOnTerminate := True;
  RegistryThread.RegistryHKey := RegistryHKey;
  RegistryThread.Memo := Memo;
  RegistryThread.OnTerminate := ThreadTerminated;
  RegistryThread.Resume;
  Result := RegistryThread;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  HKCRMemo.Clear;
  HKCUMemo.Clear;
  HKLMMemo.Clear;
  HKUMemo.Clear;
  HKCCMemo.Clear;
  rtHKCR := RunThread(HKEY_CLASSES_ROOT,HKCRMemo);
  rtHKCU := RunThread(HKEY_CURRENT_USER,HKCUMemo);
  rtHKLM := RunThread(HKEY_LOCAL_MACHINE,HKLMMemo);
  rtHKU := RunThread(HKEY_USERS,HKUMemo);
  rtHKCC := RunThread(HKEY_CURRENT_CONFIG,HKCCMemo);
end;

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  Timer1.Enabled := False;
  Application.ProcessMessages;
  If TotalDone < 1 Then
    begin
    Inc(TotalSeconds);
    StaticText1.Caption := 'Current Time: ' + IntToStr(TotalSeconds) + 's';
  end
  Else
    begin
    StaticText1.Caption := 'Total Time: ' + IntToStr(TotalSeconds) + 's';
  end;
  Timer1.Enabled := True;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Form1.DoubleBuffered := True;
  HKCRMemo.DoubleBuffered := True;
  HKCUMemo.DoubleBuffered := True;
  HKLMMemo.DoubleBuffered := True;
  HKUMemo.DoubleBuffered := True;
  HKCCMemo.DoubleBuffered := True;
end;

end.