HOW TO：從遠端調查印表機的狀態
在中型和大型公司中，任何指定的時間內可能都會有多部印表機因卡紙、缺紙或其他某個問題狀況而未作用。 Microsoft .NET Framework 的 APIs 中公開一組豐富的印表機屬性，提供方法來執行印表機狀態的快速調查。
範例
建立這類公用程式的主要步驟如下。
取得所有列印伺服器的清單。
在各伺服器之間執行迴圈 (Loop)，查詢其列印佇列。
在伺服器迴圈的每次傳遞中，會在所有伺服器佇列之間執行迴圈，以及讀取可能表示佇列目前未作用的每個屬性。
下列程式碼是程式碼片段的一部分。 為了簡化，這個範例假設具有以 CRLF 分隔的列印伺服器清單。 變數 fileOfPrintServers 是這個檔案的 StreamReader 物件。 因為每個伺服器名稱都有它自己的一行，所以任何 ReadLine 呼叫都會取得下一部伺服器的名稱，並將 StreamReader 的游標移至下一行的開頭。
在外部迴圈中，程式碼會針對最後一部列印伺服器建立 PrintServer 物件，並指定應用程式需要具有伺服器的管理權限。
.gif "注意事項") 注意事項 |
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如果有多部伺服器，則可以使用只會初始化所需要屬性的 PrintServer(String, String[], PrintSystemDesiredAccess) 建構函式，以改善效能。 |
這個範例接著會使用 GetPrintQueues 來建立所有伺服器佇列的集合，並開始對它們執行迴圈。 這個內部迴圈包含分支結構，而這個分支結構與檢查印表機狀態的兩種方式相對應：
您可以讀取型別為 PrintQueueStatus 之 QueueStatus 屬性的旗標。
您可以讀取每個相關的屬性 (如 IsOutOfPaper 和 IsPaperJammed)。
這個範例示範這兩種方法，因此應用程式會先提示使用者選擇使用其中一種方法，並會在使用者想要使用 QueueStatus 屬性的旗標時，回應 "y"。 請看以下對兩種方法的詳細說明。
最後，結果會呈現給使用者。
' Survey queue status for every queue on every print server
Dim line As String
Dim statusReport As String = vbLf & vbLf & "Any problem states are indicated below:" & vbLf & vbLf
line = fileOfPrintServers.ReadLine()
Do While line IsNot Nothing
Dim myPS As New PrintServer(line, PrintSystemDesiredAccess.AdministrateServer)
Dim myPrintQueues As PrintQueueCollection = myPS.GetPrintQueues()
statusReport = statusReport & vbLf & line
For Each pq As PrintQueue In myPrintQueues
pq.Refresh()
statusReport = statusReport & vbLf & vbTab & pq.Name & ":"
If useAttributesResponse = "y" Then
TroubleSpotter.SpotTroubleUsingQueueAttributes(statusReport, pq)
' TroubleSpotter class is defined in the complete example.
Else
TroubleSpotter.SpotTroubleUsingProperties(statusReport, pq)
End If
Next pq ' end for each print queue
line = fileOfPrintServers.ReadLine()
Loop ' end while list of print servers is not yet exhausted
fileOfPrintServers.Close()
Console.WriteLine(statusReport)
Console.WriteLine(vbLf & "Press Return to continue.")
Console.ReadLine()
// 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 屬性的旗標檢查印表機狀態，則請檢查每個相關旗標，查看是否已設定。 若要查看一組位元旗標中是否設定位元，標準的做法是執行邏輯 AND 運算，以這組旗標做為一個運算元，旗標本身則做為另一個運算元。 因為旗標本身只設定一個位元，所以邏輯 AND 運算的結果最多會設定相同的位元。 若要找出是否已設定該位元，則只要比較邏輯 AND 的結果和旗標本身即可。 如需詳細資訊，請參閱 PrintQueueStatus、& 運算子 (C# 參考) 和 FlagsAttribute。
針對每個已設定位元的屬性，程式碼會在呈現給使用者的最終報告中加入注意事項 (下面會討論在程式碼結尾呼叫的 ReportAvailabilityAtThisTime 方法)。
' Check for possible trouble states of a printer using the flags of the QueueStatus property
Friend Shared Sub SpotTroubleUsingQueueAttributes(ByRef statusReport As String, ByVal pq As PrintQueue)
If (pq.QueueStatus And PrintQueueStatus.PaperProblem) = PrintQueueStatus.PaperProblem Then
statusReport = statusReport & "Has a paper problem. "
End If
If (pq.QueueStatus And PrintQueueStatus.NoToner) = PrintQueueStatus.NoToner Then
statusReport = statusReport & "Is out of toner. "
End If
If (pq.QueueStatus And PrintQueueStatus.DoorOpen) = PrintQueueStatus.DoorOpen Then
statusReport = statusReport & "Has an open door. "
End If
If (pq.QueueStatus And PrintQueueStatus.Error) = PrintQueueStatus.Error Then
statusReport = statusReport & "Is in an error state. "
End If
If (pq.QueueStatus And PrintQueueStatus.NotAvailable) = PrintQueueStatus.NotAvailable Then
statusReport = statusReport & "Is not available. "
End If
If (pq.QueueStatus And PrintQueueStatus.Offline) = PrintQueueStatus.Offline Then
statusReport = statusReport & "Is off line. "
End If
If (pq.QueueStatus And PrintQueueStatus.OutOfMemory) = PrintQueueStatus.OutOfMemory Then
statusReport = statusReport & "Is out of memory. "
End If
If (pq.QueueStatus And PrintQueueStatus.PaperOut) = PrintQueueStatus.PaperOut Then
statusReport = statusReport & "Is out of paper. "
End If
If (pq.QueueStatus And PrintQueueStatus.OutputBinFull) = PrintQueueStatus.OutputBinFull Then
statusReport = statusReport & "Has a full output bin. "
End If
If (pq.QueueStatus And PrintQueueStatus.PaperJam) = PrintQueueStatus.PaperJam Then
statusReport = statusReport & "Has a paper jam. "
End If
If (pq.QueueStatus And PrintQueueStatus.Paused) = PrintQueueStatus.Paused Then
statusReport = statusReport & "Is paused. "
End If
If (pq.QueueStatus And PrintQueueStatus.TonerLow) = PrintQueueStatus.TonerLow Then
statusReport = statusReport & "Is low on toner. "
End If
If (pq.QueueStatus And PrintQueueStatus.UserIntervention) = PrintQueueStatus.UserIntervention Then
statusReport = statusReport & "Needs user intervention. "
End If
' Check if queue is even available at this time of day
' The method below is defined in the complete example.
ReportAvailabilityAtThisTime(statusReport, pq)
End Sub
// 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);
};
若要使用每個屬性檢查印表機狀態，則只需要讀取每個屬性，並將注意事項加入至屬性為 true 時呈現給使用者的最終報告 (下面會討論在程式碼結尾呼叫的 ReportAvailabilityAtThisTime 方法)。
' Check for possible trouble states of a printer using its properties
Friend Shared Sub SpotTroubleUsingProperties(ByRef statusReport As String, ByVal pq As PrintQueue)
If pq.HasPaperProblem Then
statusReport = statusReport & "Has a paper problem. "
End If
If Not(pq.HasToner) Then
statusReport = statusReport & "Is out of toner. "
End If
If pq.IsDoorOpened Then
statusReport = statusReport & "Has an open door. "
End If
If pq.IsInError Then
statusReport = statusReport & "Is in an error state. "
End If
If pq.IsNotAvailable Then
statusReport = statusReport & "Is not available. "
End If
If pq.IsOffline Then
statusReport = statusReport & "Is off line. "
End If
If pq.IsOutOfMemory Then
statusReport = statusReport & "Is out of memory. "
End If
If pq.IsOutOfPaper Then
statusReport = statusReport & "Is out of paper. "
End If
If pq.IsOutputBinFull Then
statusReport = statusReport & "Has a full output bin. "
End If
If pq.IsPaperJammed Then
statusReport = statusReport & "Has a paper jam. "
End If
If pq.IsPaused Then
statusReport = statusReport & "Is paused. "
End If
If pq.IsTonerLow Then
statusReport = statusReport & "Is low on toner. "
End If
If pq.NeedUserIntervention Then
statusReport = statusReport & "Needs user intervention. "
End If
' Check if queue is even available at this time of day
' The following method is defined in the complete example.
ReportAvailabilityAtThisTime(statusReport, pq)
End Sub 'end SpotTroubleUsingProperties
// 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);
};
如果需要判斷佇列目前是否可用，則可以建立 ReportAvailabilityAtThisTime 方法。
如果 StartTimeOfDay 和 UntilTimeOfDay 屬性相等，則這個方法不會有任何作用，原因是在那種情況下，印表機隨時都可以使用。 如果不同，則這個方法會取得目前時間，接著必須將這個時間轉換為午夜之後的分鐘總數，原因是 StartTimeOfDay 和 UntilTimeOfDay 屬性都是表示午夜之後分鐘總數的 Int32，而不是 DateTime 物件。 最後，這個方法會檢查目前時間是否介於開始與「結束」時間之間。
Private Shared Sub ReportAvailabilityAtThisTime(ByRef statusReport As String, ByVal pq As PrintQueue)
If pq.StartTimeOfDay <> pq.UntilTimeOfDay Then ' If the printer is not available 24 hours a day
Dim utcNow As Date = Date.UtcNow
Dim utcNowAsMinutesAfterMidnight As Int32 = (utcNow.TimeOfDay.Hours * 60) + utcNow.TimeOfDay.Minutes
' If now is not within the range of available times . . .
If Not((pq.StartTimeOfDay < utcNowAsMinutesAfterMidnight) AndAlso (utcNowAsMinutesAfterMidnight < pq.UntilTimeOfDay)) Then
statusReport = statusReport & " Is not available at this time of day. "
End If
End If
End Sub
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. ";
}
}
};