求调用外部程序及判断其完成的方法 !急 (10分)

admini · 2003-11-21

我想调用外部程序dat2mpg.exe自动把.DAT转为mpg格式，要等dat2mpg.exe转换完了这个文件后才执行下一条指令。 请教各位大哥

konhon · 2003-11-21

wjh_wy · 2003-11-21

Waiting till an application ends WaitForSingleObject If we ever need to run an external application and wait until it terminates, then we would have to do without ShellExecute and resort to more basic functions, like CreateProcess, WaitForSingleObject and CloseHandle. uses Forms, Windows; procedure TForm1.Button1Click(Sender: TObject); var   proc_info: TProcessInformation;   startinfo: TStartupInfo;   ExitCode: longword; begin   // Initialize the structures   FillChar(proc_info, sizeof(TProcessInformation), 0);   FillChar(startinfo, sizeof(TStartupInfo), 0);   startinfo.cb := sizeof(TStartupInfo);   // Attempts to create the process   if CreateProcess('c:/windows/notepad.exe', nil, nil,       nil, false, NORMAL_PRIORITY_CLASS, nil, nil,        startinfo, proc_info) <> False then begin     // The process has been successfully created     // No let's wait till it ends...     WaitForSingleObject(proc_info.hProcess, INFINITE);     // Process has finished. Now we should close it.     GetExitCodeProcess(proc_info.hProcess, ExitCode);  // Optional     CloseHandle(proc_info.hThread);     CloseHandle(proc_info.hProcess);     Application.MessageBox(       PChar(Format('Notepad finished! (Exit code=%d)', [ExitCode])),       'Info', MB_ICONINFORMATION);   end else begin     // Failure creating the process     Application.MessageBox('Couldn''t execute the '       + 'application', 'Error', MB_ICONEXCLAMATION);   end;//if end; Problems We have experienced problems with WaitForSingleObject in combination with certain applications and we had to finish them with the task manager. Other applications apparently fail to finish correctly and WaitForSingleObject never returns. Appart from that, an application does not respond to events while it waits and this means that for example the forms won't repaint... A possible workaround to these problems is checking the status of the launched application (calling GetExitCodeProcess) at intervals (in a timer event). uses Forms, Windows, StdCtrls, ExtCtrls; type TForm1 = class(TForm)   btnExecute: TButton;   btnCancel: TButton;   Timer1: TTimer;   procedure FormCreate(Sender: TObject);   procedure btnExecuteClick(Sender: TObject);   procedure Timer1Timer(Sender: TObject);   procedure btnCancelClick(Sender: TObject);   procedure FormCloseQuery(Sender: TObject;     var CanClose: Boolean); private   proc_info: TProcessInformation;   startinfo: TStartupInfo;   ExitCode: LongWord; end; implementation procedure TForm1.FormCreate(Sender: TObject); begin   btnCancel.Enabled := False;   Timer1.Enabled := False;   Timer1.Interval := 200; end; procedure TForm1.btnExecuteClick(Sender: TObject); begin   FillChar(proc_info, sizeof(TProcessInformation), 0);   FillChar(startinfo, sizeof(TStartupInfo), 0);   startinfo.cb := sizeof(TStartupInfo);   if CreateProcess(nil, 'c:/windows/notepad.exe', nil,       nil, false, CREATE_DEFAULT_ERROR_MODE       + NORMAL_PRIORITY_CLASS, nil, nil, startinfo,       proc_info) then begin     btnExecute.Enabled := False;     btnCancel.Enabled := True;     Timer1.Enabled := True;   end else begin     CloseHandle(proc_info.hProcess);     Application.MessageBox('Couldn''t execute the '       + 'application', 'Error', MB_ICONEXCLAMATION);   end; end; procedure TForm1.Timer1Timer(Sender: TObject); begin   Timer1.Enabled := False;   if GetExitCodeProcess(proc_info.hProcess, ExitCode)   then     if ExitCode = STILL_ACTIVE then       Timer1.Enabled := True     else begin       btnCancel.Enabled := False;       btnExecute.Enabled := True;       CloseHandle(proc_info.hProcess);     end   else begin     btnCancel.Enabled := False;     btnExecute.Enabled := True;     TerminateProcess(proc_info.hProcess, 0);     CloseHandle(proc_info.hProcess);   end; end; procedure TForm1.btnCancelClick(Sender: TObject); begin   Timer1.Enabled := False;   if Application.MessageBox('You should try to finish'   + ' the application normally.'#13#13'&iquest;Terminate it '   + 'anyway?', 'Warning', MB_YESNO + MB_DEFBUTTON2 +   MB_ICONQUESTION + MB_TASKMODAL) = ID_YES then begin     TerminateProcess(proc_info.hProcess, 0);     CloseHandle(proc_info.hProcess);     btnCancel.Enabled := False;     btnExecute.Enabled := True;   end else begin     Timer1.Enabled := True;   end; end; procedure TForm1.FormCloseQuery(Sender: TObject;   var CanClose: Boolean); begin   if btnCancel.Enabled then begin     btnCancelClick(Sender);     if btnCancel.Enabled then CanClose := False;   end; end;

求调用外部程序及判断其完成的方法 !急 (10分)

admini

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konhon

Unregistered / Unconfirmed

wjh_wy

Unregistered / Unconfirmed

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