delphi判断线程是否正在运行
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1 unit Unit1; 2 3 interface 4 5 uses 6 Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics, 7 Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls; 8 9 type 10 TMyThread = class(TThread)//自定义的线程 11 protected 12 procedure Execute; override; 13 end; 14 15 TForm1 = class(TForm) 16 Button1: TButton; 17 procedure Button1Click(Sender: TObject); 18 private 19 { Private declarations } 20 public 21 { Public declarations } 22 end; 23 24 var 25 Form1: TForm1; 26 mytd: TMyThread;//线程对像 27 implementation 28 29 {$R *.dfm} 30 31 //返回值:0-已释放;1-正在运行;2-已终止但未释放;3-未建立或不存在 32 function CheckThreadFreed(aThread: TThread): Byte; 33 var 34 I: DWord; 35 IsQuit: Boolean; 36 begin 37 if Assigned(aThread) then 38 begin 39 IsQuit := GetExitCodeThread(aThread.Handle, I); 40 if IsQuit then //If the function succeeds, the return value is nonzero. 41 //If the function fails, the return value is zero. 42 begin 43 if I = STILL_ACTIVE then //If the specified thread has not terminated, 44 //the termination status returned is STILL_ACTIVE. 45 Result := 1 46 else 47 Result := 2; //aThread未Free,因为Tthread.Destroy中有执行语句 48 end 49 else 50 Result := 0; //可以用GetLastError取得错误代码 51 end 52 else 53 Result := 3; 54 end; 55 56 procedure TMyThread.Execute; 57 var 58 I: Integer; 59 begin 60 for I := 0 to 500000 do 61 begin 62 Form1.Canvas.Lock; 63 Form1.Canvas.TextOut(10, 10, IntToStr(I)); 64 Form1.Canvas.Unlock; 65 end; 66 end; 67 68 procedure TForm1.Button1Click(Sender: TObject); 69 begin 70 if CheckThreadFreed(mytd)<>1 then //判断线程是否存在 71 begin 72 mytd := TMyThread.Create(True); 73 mytd.FreeOnTerminate := True; 74 mytd.Resume; 75 end; 76 end; 77 78 end.
作者:疯狂Delphi
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