unit Unit1;

interface

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

type
TForm1 = class(TForm)
Button1: TButton;
Button2: TButton;
Button3: TButton;
Button4: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
hThread:Thandle;//定义一个句柄
ThreadID:DWord;
end;

var
Form1: TForm1;

implementation

{$R *.dfm}
function MyThreadFunc(P:pointer):Longint;stdcall;
var
i:longint;
DC:HDC;
S:string;
begin
DC:=GetDC(Form1.Handle);
for i:=0 to 500000 do begin
S:=Inttostr(i);
Textout(DC,10,10,Pchar(S),length(S));
end;
ReleaseDC(Form1.Handle,DC);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
//创建线程，同时线程函数被调用
hthread:=CreateThread(nil,0,@MyThreadfunc,nil,0,ThreadID);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
SuspendThread(hThread); //挂起线程
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
ResumeThread(hThread); // 激活线程
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
TerminateThread(hThread,0); //　终止线程
end;

end.

http://blog.csdn.net/cmdasm/article/details/10003493