Delphi中的多线程允许您创建包含多个同时执行路径的应用程序。

一个普通的Delphi应用程序是单线程的，这意味着所有VCL对象都在这个单线程中访问它们的属性并执行它们的方法。要加快应用程序中的数据处理，请包括一个或多个辅助线程。

处理器线程

线程是从应用程序到处理器的通信通道。单线程程序在执行时需要双向通信（与处理器之间的通信）；多线程应用程序可以打开多个不同的通道，从而加快执行速度。

线程及；桂

当应用程序中运行多个线程时，问题是如何在执行线程后更新图形用户界面。答案在于TThread类的Synchronize方法。

要从辅助线程更新应用程序的用户界面或主线程，需要调用Synchronize方法。此技术是一种线程安全的方法，可避免访问对象属性或非线程安全的方法，或使用非执行主线程中的资源时可能出现的多线程冲突。

下面是一个示例演示，它使用几个带有进度条的按钮，每个进度条显示线程执行的当前“状态”。

unit MainU;interfaceusesWindows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,Dialogs, ComCtrls, StdCtrls, ExtCtrls;type//interceptor classTButton = class(StdCtrls.TButton)OwnedThread: TThread;ProgressBar: TProgressBar;end;TMyThread = class(TThread)privateFCounter: Integer;FCountTo: Integer;FProgressBar: TProgressBar;FOwnerButton: TButton;procedure DoProgress;procedure SetCountTo(const Value: Integer) ;procedure SetProgressBar(const Value: TProgressBar) ;procedure SetOwnerButton(const Value: TButton) ;protectedprocedure Execute; override;publicconstructor Create(CreateSuspended: Boolean) ;property CountTo: Integer read FCountTo write SetCountTo;property ProgressBar: TProgressBar read FProgressBar write SetProgressBar;property OwnerButton: TButton read FOwnerButton write SetOwnerButton;end;TMainForm = class(TForm)Button1: TButton;ProgressBar1: TProgressBar;Button2: TButton;ProgressBar2: TProgressBar;Button3: TButton;ProgressBar3: TProgressBar;Button4: TButton;ProgressBar4: TProgressBar;Button5: TButton;ProgressBar5: TProgressBar;procedure Button1Click(Sender: TObject) ;end;varMainForm: TMainForm;implementation{$R *.dfm}{ TMyThread }constructor TMyThread.Create(CreateSuspended: Boolean) ;begininherited;FCounter := 0;FCountTo := MAXINT;end;procedure TMyThread.DoProgress;varPctDone: Extended;beginPctDone := (FCounter / FCountTo) ;FProgressBar.Position := Round(FProgressBar.Step * PctDone) ;FOwnerButton.Caption := FormatFloat('0.00 %', PctDone * 100) ;end;procedure TMyThread.Execute;constInterval = 1000000;beginFreeOnTerminate := True;FProgressBar.Max := FCountTo div Interval;FProgressBar.Step := FProgressBar.Max;while FCounter < FCountTo dobeginif FCounter mod Interval = 0 then Synchronize(DoProgress) ;Inc(FCounter) ;end;FOwnerButton.Caption := 'Start';FOwnerButton.OwnedThread := nil;FProgressBar.Position := FProgressBar.Max;end;procedure TMyThread.SetCountTo(const Value: Integer) ;beginFCountTo := Value;end;procedure TMyThread.SetOwnerButton(const Value: TButton) ;beginFOwnerButton := Value;end;procedure TMyThread.SetProgressBar(const Value: TProgressBar) ;beginFProgressBar := Value;end;procedure TMainForm.Button1Click(Sender: TObject) ;varaButton: TButton;aThread: TMyThread;aProgressBar: TProgressBar;beginaButton := TButton(Sender) ;if not Assigned(aButton.OwnedThread) thenbeginaThread := TMyThread.Create(True) ;aButton.OwnedThread := aThread;aProgressBar := TProgressBar(FindComponent(StringReplace(aButton.Name, 'Button', 'ProgressBar', []))) ;aThread.ProgressBar := aProgressBar;aThread.OwnerButton := aButton;aThread.Resume;aButton.Caption := 'Pause';endelsebeginif aButton.OwnedThread.Suspended thenaButton.OwnedThread.ResumeelseaButton.OwnedThread.Suspend;aButton.Caption := 'Run';end;end;end.

感谢Jens Borrisholt提交此代码示例。