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Cómo: Supervisar de forma remota el estado de las impresoras

En cualquier momento determinado, en las compañías medianas y grandes puede haber varias impresoras que no funcionen por un atasco de papel, por falta de papel o por cualquier otra situación problemática. El conjunto enriquecido de propiedades de impresora expuesto en las APIs de Microsoft .NET Framework proporciona un medio para realizar un repaso rápido de los estados de las impresoras.

Ejemplo

Los pasos principales para crear este tipo de utilidad son los siguientes.

  1. Obtenga una lista de todos los servidores de impresión.

  2. Recorra en bucle los servidores para consultar sus colas de impresión.

  3. Dentro de cada paso del bucle de servidor, recorra en bucle todas las colas del servidor y lea cada propiedad que pueda indicar que la cola no está funcionando actualmente.

El código siguiente consiste en una serie de fragmentos de código. Para mayor simplicidad, en este ejemplo se da por hecho que existe una lista de servidores de impresión delimitada por CRLF. La variable fileOfPrintServers es un objeto StreamReader para este archivo. Puesto que cada nombre de servidor figura en su propia línea, cualquier llamada de ReadLine obtiene el nombre del servidor siguiente y mueve el cursor de StreamReader al principio de la línea siguiente.

Dentro del bucle exterior, el código crea un objeto PrintServer para el último servidor de impresión y especifica que la aplicación debe tener derechos administrativos en el servidor.

NotaNota

Si hay muchos servidores, puede mejorar el rendimiento utilizando los constructores PrintServer(String, String[], PrintSystemDesiredAccess), que inicializan únicamente las propiedades que se van a necesitar.

A continuación, en el ejemplo se utiliza el método GetPrintQueues para crear una colección de todas las colas del servidor y comienza a recorrerlas en bucle. Este bucle interno contiene una estructura de bifurcación que corresponde a las dos maneras de comprobar el estado de una impresora:

En este ejemplo se muestran ambos métodos, de modo que previamente se ha preguntado al usuario qué método desea utilizar y este ha respondido con "y" (Sí) si desea utilizar los marcadores de la propiedad QueueStatus. Consulte más adelante los detalles de los dos métodos.

Por último, se presentan los resultados al usuario.

            ' 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();

Para comprobar estado de la impresora mediante los marcadores de la propiedad QueueStatus, se comprueba cada marcador pertinente para ver si está establecido. La manera estándar de comprobar si un bit está establecido en un conjunto de indicadores de bits, es realizar la operación de AND lógico con el conjunto de marcadores como uno de los operandos y con el propio marcador como el otro operando. Puesto que el marcador únicamente tiene un bit establecido, el resultado de la operación de AND lógico es que, a lo sumo, ese mismo bit está establecido. Para averiguar si lo está o no, basta con comparar el resultado de la operación de AND lógico con el propio marcador. Para obtener más información, consulte PrintQueueStatus, Operador & (Referencia de C#) y FlagsAttribute.

Para cada atributo cuyo bit está establecido, el código agrega un aviso al informe final que se presentará al usuario. (El método ReportAvailabilityAtThisTime al que se llama al final del código se aborda más adelante.)

        ' 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);
   };

Para comprobar estado de la impresora mediante cada propiedad, basta con leer cada una de ellas y agregar una nota al informe final que se presentará al usuario en caso de que la propiedad sea true. (El método ReportAvailabilityAtThisTime al que se llama al final del código se aborda más adelante.)

        ' 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);
   };

Se creó el método ReportAvailabilityAtThisTime por si se necesita determinar si la cola está disponible a esta hora del día.

El método no hará nada si las propiedades StartTimeOfDay y UntilTimeOfDay son iguales, porque en ese caso significa que la impresora está disponible en todo momento. Si son diferentes, el método obtiene la hora actual que, a continuación, se tiene que convertir a minutos totales transcurridos desde la pasada medianoche; esto es porque las propiedades StartTimeOfDay y UntilTimeOfDay son objetos Int32 que representan minutos transcurridos desde la medianoche, no objetos DateTime. Por último, el método comprueba si la hora actual se encuentra entre los momentos de inicio y "hasta".

        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. ";
         }
      }
   };

Vea también

Referencia

StartTimeOfDay

UntilTimeOfDay

DateTime

PrintQueueStatus

Operador & (Referencia de C#)

FlagsAttribute

GetPrintQueues

PrintServer

LocalPrintServer

EnumeratedPrintQueueTypes

PrintQueue

Conceptos

Documentos en WPF

Información general sobre impresión