如何让德尔福等待30秒再继续(how to make delphi wait 30sec then

我试图做一个无限循环，但我希望循环每30秒运行。循环将开始。 if语句发生，一些信息的一串将被改变。然后循环必须暂停30秒，然后循环将再次启动。这必须永远持续下去。

我正在寻找一种方式来暂停 30秒的循环，然后继续。任何好的建议将不胜感激。

编辑＃1

该方案显示基于日期和时间的“特殊”的信息：随着时间的改变信息改变：06：00 =数学; 07:30 =生物学。该方案还显示你离开，直到下一节课开始时间。因此，该程序需要持续运行，从而它知道到底是什么时期，它是和多少时间留到下一期更新时间。

编辑＃2

~~我想提出一个“刷新”，使剧本~~我想，这样它不会持续运行和吃RAM中的脚本在设置的时间间隔被调用。这个间隔必须是30秒。

Answer 1:

如果你有一些代码块的图形用户界面，你可以使用一个后台线程和事件提供非阻塞计时器。

创建一个新的窗体应用程序，并把TMemo组件的形式。这个例子将添加一个新行与当前时间到你TMemo 。

主要形式有：

unit u_frm_main;

interface

uses
  u_workthread,
  SysUtils,
  Windows,
  Forms,
  SyncObjs, Classes, Controls, StdCtrls;

type
  TForm1 = class(TForm)
    Memo1: TMemo;
    procedure FormCreate(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    { Private declarations }
    Worker : TWorkThread;
    procedure ShowData;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.ShowData;
begin
 // do whatever you need to do here... 
 // show current time in memo
 Memo1.Lines.Add(FormatDateTime('HH:NN:SS', Now));
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
 // create our worker thread and start it
 Worker := TWorkThread.Create(3, ShowData);
 Worker.Start;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
 // signal our worker thread that we are done here
 Worker.ThreadEvent.SetEvent;
 // terminate and wait
 Worker.Terminate;
 Worker.WaitFor;
end;

end.

工作线程：

unit u_workthread;

interface

uses
  SysUtils,
  SyncObjs,
  Classes;

type
  TWorkProc = procedure of object;

  TWorkThread = class(TThread)
  private
    { Private declarations }
    Counter   : Integer;
    FTimeout  : Integer;
    FEventProc: TWorkProc;
    procedure DoWork;
  protected
    procedure Execute; override;
  public
    ThreadEvent : TEvent;
    constructor Create(TimeoutSeconds : Integer; EventProc: TWorkProc ); // timeout in seconds
    destructor Destroy; override;
  end;

implementation

procedure TWorkThread.DoWork;
begin
 // put your GUI blocking code in here. Make sure you never call GUI elements from this procedure
 //DoSomeLongCalculation();
end;

procedure TWorkThread.Execute;
begin
 Counter := 0;
 while not Terminated do
  begin
   if ThreadEvent.WaitFor(FTimeout) = wrTimeout then
    begin 
     DoWork;
     // now inform our main Thread that we have data
     Synchronize(FEventProc);
    end;
   else
    // ThreadEvent has been signaled, exit our loop
    Break;
  end;
end;

constructor TWorkThread.Create(TimeoutSeconds : Integer; EventProc: TWorkProc);
begin
 ThreadEvent := TEvent.Create(nil, True, False, '');
 // Convert to milliseconds
 FTimeout := TimeoutSeconds * 1000;
 FEventProc:= EventProc;
 // call inherited constructor with CreateSuspended as True
 inherited Create(True);
end;

destructor TWorkThread.Destroy;
begin
 ThreadEvent.Free;
 inherited;
end;


end.