如何:远程调查打印机的状态
更新:2007 年 11 月
在任何给定时间,大中型公司都可能会有多台打印机由于夹纸、缺纸或者某种其他异常情况而无法工作。Microsoft .NET Framework的 API 中公开了一组丰富的打印机属性,通过这些属性可以快速调查打印机的状态。
示例
下面是创建这种实用工具的主要步骤。
获取所有打印服务器的列表。
遍历各服务器以查询其打印队列。
在服务器遍历的每个处理过程中,遍历所有服务器的队列,并读取每个可能指示队列当前未工作的属性。
下面的代码由一系列代码段组成。有关完整示例,请参见 调查打印机状态的示例。
为简单起见,此示例假设存在一个用 CRLF 分隔的打印服务器列表。变量 fileOfPrintServers 是该文件的一个 StreamReader 对象。由于每个服务器名称都在其各自的行上,因此每次调用 ReadLine 时都会获取下一台服务器的名称,并将 StreamReader 的游标移到下一行的开头。
在外部循环中,该代码为最后一台打印服务器创建一个 PrintServer 对象,并指定该应用程序将对最后一台打印服务器具有管理权限。
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如果存在多台服务器,则可以通过使用 PrintServer(String, array<String[], PrintSystemDesiredAccess) 构造函数来改进性能,这些构造函数仅对您将需要的属性进行初始化。 |
此示例随后使用 GetPrintQueues 来创建一个包含所有服务器队列的集合,并开始遍历它们。内部循环包含一个与打印机状态的两种检查方法相对应的分支结构:
您可以读取类型为 PrintQueueStatus 的 QueueStatus 属性的标志。
您可以读取每个相关属性,如 IsOutOfPaper 和 IsPaperJammed。
此示例对这两种方法均进行了演示,因此用户在这之前会被询问要使用哪种方法,如果用户希望使用 QueueStatus 属性的标志,则可以回答“y”(是)。下面详细介绍了这两种方法。
最后,结果将呈现给用户。
// Survey queue status for every queue on every print server
String line;
String statusReport = "\n\nAny problem states are indicated below:\n\n";
while ((line = fileOfPrintServers.ReadLine()) != null)
{
PrintServer myPS = new PrintServer(line, PrintSystemDesiredAccess.AdministrateServer);
PrintQueueCollection myPrintQueues = myPS.GetPrintQueues();
statusReport = statusReport + "\n" + line;
foreach (PrintQueue pq in myPrintQueues)
{
pq.Refresh();
statusReport = statusReport + "\n\t" + pq.Name + ":";
if (useAttributesResponse == "y")
{
TroubleSpotter.SpotTroubleUsingQueueAttributes(ref statusReport, pq);
// TroubleSpotter class is defined in the complete example.
}
else
{
TroubleSpotter.SpotTroubleUsingProperties(ref statusReport, pq);
}
}// end for each print queue
}// end while list of print servers is not yet exhausted
fileOfPrintServers.Close();
Console.WriteLine(statusReport);
Console.WriteLine("\nPress Return to continue.");
Console.ReadLine();
// Survey queue status for every queue on every print server
System::String^ line;
System::String^ statusReport = "\n\nAny problem states are indicated below:\n\n";
while ((line = fileOfPrintServers->ReadLine()) != nullptr)
{
System::Printing::PrintServer^ myPS = gcnew System::Printing::PrintServer(line, PrintSystemDesiredAccess::AdministrateServer);
System::Printing::PrintQueueCollection^ myPrintQueues = myPS->GetPrintQueues();
statusReport = statusReport + "\n" + line;
for each (System::Printing::PrintQueue^ pq in myPrintQueues)
{
pq->Refresh();
statusReport = statusReport + "\n\t" + pq->Name + ":";
if (useAttributesResponse == "y")
{
TroubleSpotter::SpotTroubleUsingQueueAttributes(statusReport, pq);
// TroubleSpotter class is defined in the complete example.
} else
{
TroubleSpotter::SpotTroubleUsingProperties(statusReport, pq);
}
}
}
fileOfPrintServers->Close();
Console::WriteLine(statusReport);
Console::WriteLine("\nPress Return to continue.");
Console::ReadLine();
若要使用 QueueStatus 属性的标志来检查打印机状态,可以通过检查每个相关标志来查看它是否已经设置。如需检查是否在一组位标志中设置了某个位,标准方法是将这组标志作为一个操作数,将需要检查的标志本身作为另一个操作数,对它们执行逻辑“与”运算。由于该标志本身只设置了一个位,因此逻辑“与”运算的结果是至多设置了同一个位。若要确定是否设置了该位,只需将逻辑“与”运算的结果与该标志本身进行比较。有关更多信息,请参见 PrintQueueStatus、& 运算符(C# 参考) 和 FlagsAttribute。
对于每个设置了位的属性,该代码会在最终报告中添加一个将呈现给用户的通知 (下面将讨论在该代码末尾处调用的 ReportAvailabilityAtThisTime 方法)。
// Check for possible trouble states of a printer using the flags of the QueueStatus property
internal static void SpotTroubleUsingQueueAttributes(ref String statusReport, PrintQueue pq)
{
if ((pq.QueueStatus & PrintQueueStatus.PaperProblem) == PrintQueueStatus.PaperProblem)
{
statusReport = statusReport + "Has a paper problem. ";
}
if ((pq.QueueStatus & PrintQueueStatus.NoToner) == PrintQueueStatus.NoToner)
{
statusReport = statusReport + "Is out of toner. ";
}
if ((pq.QueueStatus & PrintQueueStatus.DoorOpen) == PrintQueueStatus.DoorOpen)
{
statusReport = statusReport + "Has an open door. ";
}
if ((pq.QueueStatus & PrintQueueStatus.Error) == PrintQueueStatus.Error)
{
statusReport = statusReport + "Is in an error state. ";
}
if ((pq.QueueStatus & PrintQueueStatus.NotAvailable) == PrintQueueStatus.NotAvailable)
{
statusReport = statusReport + "Is not available. ";
}
if ((pq.QueueStatus & PrintQueueStatus.Offline) == PrintQueueStatus.Offline)
{
statusReport = statusReport + "Is off line. ";
}
if ((pq.QueueStatus & PrintQueueStatus.OutOfMemory) == PrintQueueStatus.OutOfMemory)
{
statusReport = statusReport + "Is out of memory. ";
}
if ((pq.QueueStatus & PrintQueueStatus.PaperOut) == PrintQueueStatus.PaperOut)
{
statusReport = statusReport + "Is out of paper. ";
}
if ((pq.QueueStatus & PrintQueueStatus.OutputBinFull) == PrintQueueStatus.OutputBinFull)
{
statusReport = statusReport + "Has a full output bin. ";
}
if ((pq.QueueStatus & PrintQueueStatus.PaperJam) == PrintQueueStatus.PaperJam)
{
statusReport = statusReport + "Has a paper jam. ";
}
if ((pq.QueueStatus & PrintQueueStatus.Paused) == PrintQueueStatus.Paused)
{
statusReport = statusReport + "Is paused. ";
}
if ((pq.QueueStatus & PrintQueueStatus.TonerLow) == PrintQueueStatus.TonerLow)
{
statusReport = statusReport + "Is low on toner. ";
}
if ((pq.QueueStatus & PrintQueueStatus.UserIntervention) == PrintQueueStatus.UserIntervention)
{
statusReport = statusReport + "Needs user intervention. ";
}
// Check if queue is even available at this time of day
// The method below is defined in the complete example.
ReportAvailabilityAtThisTime(ref statusReport, pq);
}
internal:
// Check for possible trouble states of a printer using the flags of the QueueStatus property
static void SpotTroubleUsingQueueAttributes (System::String^% statusReport, System::Printing::PrintQueue^ pq)
{
if ((pq->QueueStatus & PrintQueueStatus::PaperProblem) == PrintQueueStatus::PaperProblem)
{
statusReport = statusReport + "Has a paper problem. ";
}
if ((pq->QueueStatus & PrintQueueStatus::NoToner) == PrintQueueStatus::NoToner)
{
statusReport = statusReport + "Is out of toner. ";
}
if ((pq->QueueStatus & PrintQueueStatus::DoorOpen) == PrintQueueStatus::DoorOpen)
{
statusReport = statusReport + "Has an open door. ";
}
if ((pq->QueueStatus & PrintQueueStatus::Error) == PrintQueueStatus::Error)
{
statusReport = statusReport + "Is in an error state. ";
}
if ((pq->QueueStatus & PrintQueueStatus::NotAvailable) == PrintQueueStatus::NotAvailable)
{
statusReport = statusReport + "Is not available. ";
}
if ((pq->QueueStatus & PrintQueueStatus::Offline) == PrintQueueStatus::Offline)
{
statusReport = statusReport + "Is off line. ";
}
if ((pq->QueueStatus & PrintQueueStatus::OutOfMemory) == PrintQueueStatus::OutOfMemory)
{
statusReport = statusReport + "Is out of memory. ";
}
if ((pq->QueueStatus & PrintQueueStatus::PaperOut) == PrintQueueStatus::PaperOut)
{
statusReport = statusReport + "Is out of paper. ";
}
if ((pq->QueueStatus & PrintQueueStatus::OutputBinFull) == PrintQueueStatus::OutputBinFull)
{
statusReport = statusReport + "Has a full output bin. ";
}
if ((pq->QueueStatus & PrintQueueStatus::PaperJam) == PrintQueueStatus::PaperJam)
{
statusReport = statusReport + "Has a paper jam. ";
}
if ((pq->QueueStatus & PrintQueueStatus::Paused) == PrintQueueStatus::Paused)
{
statusReport = statusReport + "Is paused. ";
}
if ((pq->QueueStatus & PrintQueueStatus::TonerLow) == PrintQueueStatus::TonerLow)
{
statusReport = statusReport + "Is low on toner. ";
}
if ((pq->QueueStatus & PrintQueueStatus::UserIntervention) == PrintQueueStatus::UserIntervention)
{
statusReport = statusReport + "Needs user intervention. ";
}
// Check if queue is even available at this time of day
// The method below is defined in the complete example.
ReportAvailabilityAtThisTime(statusReport, pq);
};
若要使用每个属性来检查打印机状态,只需读取每个属性,如果该属性为 true,则在最终报告中添加一个将呈现给用户的说明 (下面将讨论在该代码末尾处调用的 ReportAvailabilityAtThisTime 方法)。
// Check for possible trouble states of a printer using its properties
internal static void SpotTroubleUsingProperties(ref String statusReport, PrintQueue pq)
{
if (pq.HasPaperProblem)
{
statusReport = statusReport + "Has a paper problem. ";
}
if (!(pq.HasToner))
{
statusReport = statusReport + "Is out of toner. ";
}
if (pq.IsDoorOpened)
{
statusReport = statusReport + "Has an open door. ";
}
if (pq.IsInError)
{
statusReport = statusReport + "Is in an error state. ";
}
if (pq.IsNotAvailable)
{
statusReport = statusReport + "Is not available. ";
}
if (pq.IsOffline)
{
statusReport = statusReport + "Is off line. ";
}
if (pq.IsOutOfMemory)
{
statusReport = statusReport + "Is out of memory. ";
}
if (pq.IsOutOfPaper)
{
statusReport = statusReport + "Is out of paper. ";
}
if (pq.IsOutputBinFull)
{
statusReport = statusReport + "Has a full output bin. ";
}
if (pq.IsPaperJammed)
{
statusReport = statusReport + "Has a paper jam. ";
}
if (pq.IsPaused)
{
statusReport = statusReport + "Is paused. ";
}
if (pq.IsTonerLow)
{
statusReport = statusReport + "Is low on toner. ";
}
if (pq.NeedUserIntervention)
{
statusReport = statusReport + "Needs user intervention. ";
}
// Check if queue is even available at this time of day
// The following method is defined in the complete example.
ReportAvailabilityAtThisTime(ref statusReport, pq);
}//end SpotTroubleUsingProperties
internal:
// Check for possible trouble states of a printer using its properties
static void SpotTroubleUsingProperties (System::String^% statusReport, System::Printing::PrintQueue^ pq)
{
if (pq->HasPaperProblem)
{
statusReport = statusReport + "Has a paper problem. ";
}
if (!(pq->HasToner))
{
statusReport = statusReport + "Is out of toner. ";
}
if (pq->IsDoorOpened)
{
statusReport = statusReport + "Has an open door. ";
}
if (pq->IsInError)
{
statusReport = statusReport + "Is in an error state. ";
}
if (pq->IsNotAvailable)
{
statusReport = statusReport + "Is not available. ";
}
if (pq->IsOffline)
{
statusReport = statusReport + "Is off line. ";
}
if (pq->IsOutOfMemory)
{
statusReport = statusReport + "Is out of memory. ";
}
if (pq->IsOutOfPaper)
{
statusReport = statusReport + "Is out of paper. ";
}
if (pq->IsOutputBinFull)
{
statusReport = statusReport + "Has a full output bin. ";
}
if (pq->IsPaperJammed)
{
statusReport = statusReport + "Has a paper jam. ";
}
if (pq->IsPaused)
{
statusReport = statusReport + "Is paused. ";
}
if (pq->IsTonerLow)
{
statusReport = statusReport + "Is low on toner. ";
}
if (pq->NeedUserIntervention)
{
statusReport = statusReport + "Needs user intervention. ";
}
// Check if queue is even available at this time of day
// The following method is defined in the complete example.
ReportAvailabilityAtThisTime(statusReport, pq);
};
创建 ReportAvailabilityAtThisTime 方法的目的在于让您确定队列在当前时间是否可用。
如果 StartTimeOfDay 属性和 UntilTimeOfDay 属性相等,该方法将不执行任何操作;因为在这种情况下,打印机将一直可用。如果这两个属性不同,则该方法将获取当前时间,当前时间随后将必须转换为自午夜以来的总分钟数,因为 StartTimeOfDay 属性和 UntilTimeOfDay 属性是表示自午夜以来的总分钟数的 Int32 值,而不是 DateTime 对象。最后,该方法将查看当前的时间是否介于开始时间和截止时间之间。
private static void ReportAvailabilityAtThisTime(ref String statusReport, PrintQueue pq)
{
if (pq.StartTimeOfDay != pq.UntilTimeOfDay) // If the printer is not available 24 hours a day
{
DateTime utcNow = DateTime.UtcNow;
Int32 utcNowAsMinutesAfterMidnight = (utcNow.TimeOfDay.Hours * 60) + utcNow.TimeOfDay.Minutes;
// If now is not within the range of available times . . .
if (!((pq.StartTimeOfDay < utcNowAsMinutesAfterMidnight)
&&
(utcNowAsMinutesAfterMidnight < pq.UntilTimeOfDay)))
{
statusReport = statusReport + " Is not available at this time of day. ";
}
}
}
private:
static void ReportAvailabilityAtThisTime (System::String^% statusReport, System::Printing::PrintQueue^ pq)
{
if (pq->StartTimeOfDay != pq->UntilTimeOfDay)
{
System::DateTime utcNow = DateTime::UtcNow;
System::Int32 utcNowAsMinutesAfterMidnight = (utcNow.TimeOfDay.Hours * 60) + utcNow.TimeOfDay.Minutes;
// If now is not within the range of available times . . .
if (!((pq->StartTimeOfDay < utcNowAsMinutesAfterMidnight) && (utcNowAsMinutesAfterMidnight < pq->UntilTimeOfDay)))
{
statusReport = statusReport + " Is not available at this time of day. ";
}
}
};
请参见
概念
Windows Presentation Foundation 中的文档