EnumJobs取不到打印页数？(内附程序)(50分)

以下程序取到的页数TotalPages始终为0，为什么？<br>function TGetJobsNT.GetJob: string;<br>const<br> &nbsp;InfoLevel = 1;<br> &nbsp;FirstJob = 0;<br> &nbsp;LastJob = 19;<br>var<br> &nbsp;Jobs: array[FirstJob..LastJob] of TJobInfo1;<br> &nbsp;BytesNeeded, NumJobs: Dword;<br> &nbsp;hPrinter: THandle;<br> &nbsp;JobsRecord: string;<br>begin<br> &nbsp;JobsRecord := '';<br> &nbsp;if OpenPrinter(Pchar(FPrinterName), hPrinter, nil) then<br> &nbsp;begin<br> &nbsp; &nbsp;WaitForPrinterChange(hPrinter, PRINTER_CHANGE_ADD_JOB);<br> &nbsp; &nbsp;if EnumJobs(hPrinter, FirstJob, LastJob + 1, InfoLevel, @Jobs, SizeOf(Jobs),<br> &nbsp; &nbsp; &nbsp;BytesNeeded, NumJobs) then<br> &nbsp; &nbsp;begin<br> &nbsp; &nbsp; &nbsp;if NumJobs &lt;&gt; 0 then<br> &nbsp; &nbsp; &nbsp;begin<br> &nbsp; &nbsp; &nbsp; &nbsp;with Jobs[NumJobs - 1] do<br> &nbsp; &nbsp; &nbsp; &nbsp;begin<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;JobsRecord := JobsRecord + StrPas(pDocument) + #9;<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;JobsRecord := JobsRecord + StrPas(pPrinterName) + #9;<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;JobsRecord := JobsRecord + StrPas(pMachineName) + #9;<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;JobsRecord := JobsRecord + StrPas(pUserName) + #9;<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;JobsRecord := JobsRecord + IntToStr(TotalPages) + #9;<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;JobsRecord := JobsRecord +<br> &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;DateTimeToStr(SystemTimeToDateTime(Submitted) + 8 / 24) + #9;<br> &nbsp; &nbsp; &nbsp; &nbsp;end;<br> &nbsp; &nbsp; &nbsp;end;<br> &nbsp; &nbsp;end;<br> &nbsp; &nbsp;ClosePrinter(hPrinter);<br> &nbsp;end;<br> &nbsp;Result := JobsRecord;<br>end;

使用定时器。<br> &nbsp; 执行一下你的程序。试试，如果还是零，程序错误。估计是打印机读取不正确。<br>名称不对。

TO：蓝叶菱<br>　　程序能对打印任务做出反应，只是不能正确得到页数。<br>　　

我怎么没有遇见过，<br> &nbsp;以前好像也有过，不过我用定时器，每秒都读取页数，结果是正确的。

TO：蓝叶菱<br>　用定时器反复测试之后，已经能够取到页数了。<br>虽然稳定性不高，同一个任务有时会取到很多条，但你的分是少不了了。<br>请到这里取分：http://www.delphibbs.com/delphibbs/dispq.asp?lid=3378581<br><br>在这里还想同大家讨论一下<br>WaitForPrinterChange(hPrinter, PRINTER_CHANGE_ADD_JOB);<br>理论上这样触发程序应该是更科学的，但是为什么之后取不到页数。

以前也要写这类程序。当时，朋友建议我使用，FindFirstPrinterChangeNotification这个东东～～

帮你顶一下吧　呵呵　

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