delphi 多线程（TThread类的实现）实例

再做个实例总结下：

用多线程类实现，在三个PaintBox上画椭圆。

unit Unit1;

interface

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

Dialogs, StdCtrls, ExtCtrls;

type

TMyThread = class(TThread)

private

FNum:Integer;

protected

procedure Execute;override;

procedure Run;

procedure SetNum(Value:integer); {设置Num}

function GetNum:integer; {获取Num}

constructor Create(Aswith:Boolean;ANum:Integer); {给创建方法添加一个参数用于传递}

public

end;

TForm1 = class(TForm)

pb1: TPaintBox;

pb2: TPaintBox;

pb3: TPaintBox;

btn1: TButton;

procedure btn1Click(Sender: TObject);

procedure FormDestroy(Sender: TObject);

private

{ Private declarations }

public

{ Public declarations }

end;

var

Form1: TForm1;

implementation

{$R *.dfm}

uses SyncObjs;

const

colors:array[0..2] of TColor =(clRed,clGreen,clBlue);

var

MyThread:TMyThread;

paintArr:array[0..2] of TPaintBox;

// MyThreadArr:array[0..2] of TMyThread; {也可用数组多个线程进行}

Mutex:TMutex;

procedure TForm1.btn1Click(Sender: TObject);

var

i:integer;

begin

if Assigned(Mutex) then Mutex.Free; {如果存在，先释放}

Mutex:=TMutex.Create(False); {创建互斥体，参数为创建者先不占用}

Repaint; {重画窗体}

paintArr[0]:=pb1; {把PaintBox1给数组paintArr[0]}

paintArr[1]:=pb2;

paintArr[2]:=pb3;

for i := Low(paintArr )to High(paintArr) do

begin

MyThread:=TMyThread.Create(False,i); {如果声明了线程数组类，可以在这里一起做循环多个线程操作}

end;

{ TMyThread }

constructor TMyThread.Create(ASwith: Boolean; ANum: Integer);

begin

inherited Create(Aswith); {继承并传参}

SetNum(ANum); {设置字段Num}

end;

procedure TMyThread.Execute;

begin

inherited;

FreeOnTerminate:=True;

Run;

end;

function TMyThread.GetNum: integer;

begin

Result:=FNum;

end;

procedure TMyThread.Run;

var

i,n,x1,x2,y1,y2:integer;

begin

n:=GetNum;

paintArr[n].Color:=Colors[n];

for i := 0 to 200 do

begin

if Mutex.WaitFor(INFINITE)=wrSignaled then {判断互斥体有没有被占用}

begin

with paintArr[n] do

begin

x1:=Random(Width);y1:=Random(Height);

x2:=Random(Width);y2:=Random(Height);

Canvas.Lock;

Canvas.Ellipse(x1,y1,x2,y2);

Canvas.Unlock;

Sleep(10);

end;

Mutex.Release; {释放放这里为每进行一次，释放，谁拿到谁用}

end;

// Mutex.Release; {释放放这里为每进行一轮循环，释放，相当于排队进行}

end;

procedure TMyThread.SetNum(Value: integer);

begin

FNum:=Value;

end;

procedure TForm1.FormDestroy(Sender: TObject);

begin

Mutex.Free;

end;

end.

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