Delphi线程优先级
描述
这个例子展示了如何创建一个线程并以低于主执行线程的优先级启动它。将线程的FreeOnTerminate属性设置为true，这样当线程完成时就不需要释放线程。必须将procedure Execute;Tthread的扩展类加入override（procedure Execute; override;），否则将导致“Abstract Error”。要创建它，请选择File > New > Other > Thread Object菜单
主要代码
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 |
procedure TForm1.Button1Click(Sender: TObject); //运行MyProcess begin if (mythreadRunning = False) then begin mythreadRunning := True; MyProcess := TMyThread.Create(True); { 创建线程并挂起. } MyProcess.FreeOnTerminate := True; { 运行结束后自动结束线程. } MyProcess.Priority := tpLower; { 将优先级设置为低于正常值. } MyProcess.Resume; { 运行线程 } end else MessageDlg('此线程仍在运行!', mtInformation, [mbOk], 0); end; procedure TForm1.Button2Click(Sender: TObject); //主线程 运行后界面UI将冻结 var I: Integer; begin Form1.Memo2.Lines.Add('在主流程中在10秒内运行一些工作:'); for I := 0 to 10 do begin Form1.Memo2.Lines.Add('主线程： ' + InttoStr(I)); Sleep(1000); end; end; procedure TForm1.Button3Click(Sender: TObject);//运行YouProcess begin if (youthreadRunning = False) then begin youthreadRunning := True; YouProcess := TYouThread.Create(True); { 创建线程并挂起. } YouProcess.FreeOnTerminate := True; { 运行结束后自动结束线程. } YouProcess.Priority := tpLower; { 将优先级设置为低于正常值. } YouProcess.Resume; { 运行线程. } end else MessageDlg('此线程仍在运行!', mtInformation, [mbOk], 0); end; procedure TForm1.Button4Click(Sender: TObject); //停止MyProcess begin if mythreadRunning then MyProcess.Terminate(); end; procedure TForm1.Button5Click(Sender: TObject); //停止YouProcess begin if youthreadRunning then YouProcess.Terminate(); end; procedure TForm1.FormCreate(Sender: TObject); begin mythreadRunning := False; youthreadRunning := False; end; { TMyThread } procedure TMyThread.Execute; var I: Integer; begin Form1.Memo1.Lines.Add('进程已运行了:'); for I := 0 to 10 do begin if Terminated then break; Form1.Memo1.Lines.Add('低优先级进程 ' + InttoStr(I)); Sleep(1000); end; mythreadRunning := False; end; { TYouThread } procedure TYouThread.Execute; var I: Integer; begin Form1.Memo3.Lines.Add('第二个低优先级进程已运行了:'); for I := 0 to 10 do begin if Terminated then break; Form1.Memo3.Lines.Add('第二个低优先级进程 ' + InttoStr(I)); Sleep(1000); end; youthreadRunning := False; end; |
