为什么线程在这个控制台应用程序中连续运行?

我正在创建一个控制台应用程序,它需要运行几个线程才能完成一个任务。我的问题是线程一个接一个地运行(thread1 start->工作->结束并只启动线程2),而不是同时运行所有线程。另外,我不希望有超过10个线程同时工作(性能问题)。下面是控制台应用程序和所用数据模块的示例代码。我的申请也是这样。我使用了datamodule,因为线程完成后,我必须用这些信息填充数据库。代码中也有注释来解释做某事的原因。

    program Project2;

{$APPTYPE CONSOLE}

uses
  SysUtils,
  Unit1 in 'Unit1.pas' {DataModule1: TDataModule};

var dm:TDataModule1;
begin
   dm:=TDataModule1.Create(nil);
   try
     dm.execute;
   finally
    FreeAndNil(dm);
   end;
end.

    unit Unit1;

interface

uses
  SysUtils, Classes, SyncObjs, Windows, Forms;

var   FCritical: TRTLCriticalSection;//accessing the global variables  

type
  TTestThread = class(TThread)
  protected
    procedure Execute;override;
  end;
  TDataModule1 = class(TDataModule)
    procedure DataModuleCreate(Sender: TObject);
    procedure DataModuleDestroy(Sender: TObject);
  private
    { Déclarations privées }
  public

    procedure execute;
    procedure CreateThread();
    procedure Onterminatethrd(Sender: TObject);
  end;

var
  DataModule1       : TDataModule1;
  FthreadCount      : Integer;  //know how many threads are running


implementation

{$R *.dfm}

{ TTestThread }

procedure TTestThread.Execute;
var
  f                 : TextFile;
  i                 : integer;
begin
  EnterCriticalSection(fcritical);
  AssignFile(f, 'd:\a' + inttostr(FthreadCount) + '.txt');
  LeaveCriticalSection(fcritical);
  Rewrite(f);
  try
    i := 0;
    while i <= 1000000 do // do some work...
      Inc(i);
    Writeln(f, 'done');
  finally
    CloseFile(f);
  end;
end;

{ TDataModule1 }

procedure TDataModule1.CreateThread;
var
  aThrd             : TTestThread;
begin
  aThrd := TTestThread.Create(True);
  aThrd.FreeOnTerminate := True;
  EnterCriticalSection(fcritical);
  Inc(FthreadCount);
  LeaveCriticalSection(fcritical);
  aThrd.OnTerminate:=Onterminatethrd;
  try
    aThrd.Resume;
  except
    FreeAndNil(aThrd);
  end;
end;

procedure TDataModule1.Onterminatethrd(Sender: TObject);
begin
  EnterCriticalSection(fcritical);
  Dec(FthreadCount);
  LeaveCriticalSection(fcritical);
end;

procedure TDataModule1.DataModuleCreate(Sender: TObject);
begin
  InitializeCriticalSection(fcritical);
end;

procedure TDataModule1.DataModuleDestroy(Sender: TObject);
begin
  DeleteCriticalSection(fcritical);
end;

procedure TDataModule1.execute;
var
  i                 : integer;
begin
  i := 0;
  while i < 1000 do
  begin
    while (FthreadCount = 10) do
      Application.ProcessMessages;//wait for an thread to finish. max threads at a //time =10

    CreateThread;

    EnterCriticalSection(fcritical);
    Inc(i);
    LeaveCriticalSection(fcritical);

    while FthreadCount > 0 do //wait for all threads to finish in order to close the //main thread
    begin
      Application.ProcessMessages;
      CheckSynchronize;
    end;
  end;
end;

end.

有人能给我个建议吗?