禁止用戶打印

Question

我已經在.net中創建了一個應用程序，以使用以下參考資料中的DLL來監視打印機中的作業：

http://www.codeproject.com/Articles/51085/Monitor-jobs-in-a-printer-queue-NET?fid=1556859&select=4799234

我的問題是：在每天打印5次之后，如何延遲或阻止用戶打印？

知道打印作業將保存在數據庫中。

感謝您的幫助。

Answer 1

可以使用FindFirstPrinterChangeNotification函數編寫一個相當簡單的程序，該函數監視用戶可用的所有打印機。 它應注意PRINTER_CHANGE_ADD_JOB事件，該事件指示已開始打印作業。 一旦用戶超出標准，您的程序便會刪除該用戶啟動的所有新打印作業。 我認為最好通知用戶，而不是僅靜默刪除其打印作業。

這不會阻止用戶嘗試打印，但是最終結果相同。 在您的應用程序允許之前，不會產生紙張。

Answer 2

解決了 ！ 我使用以下方法來解決我的問題：

暫停打印機作業，請致電：

 Public Shared Function PausePrintJob(printerName As String, printJobID As Integer) As Boolean 
        Dim isActionPerformed As Boolean = False
        Dim searchQuery As String = "SELECT * FROM Win32_PrintJob"
        Dim searchPrintJobs As New ManagementObjectSearcher(searchQuery)
        Dim prntJobCollection As ManagementObjectCollection = searchPrintJobs.[Get]()
        For Each prntJob As ManagementObject In prntJobCollection
            Dim jobName As System.String = prntJob.Properties("Name").Value.ToString()

            Dim splitArr As Char() = New Char(0) {}
            splitArr(0) = Convert.ToChar(",")
            Dim prnterName As String = jobName.Split(splitArr)(0)
            Dim prntJobID As Integer = Convert.ToInt32(jobName.Split(splitArr)(1))
            Dim documentName As String = prntJob.Properties("Document").Value.ToString()
            If [String].Compare(prnterName, printerName, True) = 0 Then
                If prntJobID = printJobID Then
                    prntJob.InvokeMethod("Pause", Nothing)
                    isActionPerformed = True
                    Exit For
                End If
            End If
        Next
        Return isActionPerformed
    End Function

為了取消打印機作業，我使用了以下方法：

    Public Shared Function CancelPrintJob(printerName As String, printJobID As Integer) As Boolean
        Dim isActionPerformed As Boolean = False
        Dim searchQuery As String = "SELECT * FROM Win32_PrintJob"
        Dim searchPrintJobs As New ManagementObjectSearcher(searchQuery)
        Dim prntJobCollection As ManagementObjectCollection = searchPrintJobs.[Get]()
        For Each prntJob As ManagementObject In prntJobCollection
            Dim jobName As System.String = prntJob.Properties("Name").Value.ToString()

            Dim splitArr As Char() = New Char(0) {}
            splitArr(0) = Convert.ToChar(",")
            Dim prnterName As String = jobName.Split(splitArr)(0)
            Dim prntJobID As Integer = Convert.ToInt32(jobName.Split(splitArr)(1))
            Dim documentName As String = prntJob.Properties("Document").Value.ToString()
            If [String].Compare(prnterName, printerName, True) = 0 Then
                If prntJobID = printJobID Then                 
                    prntJob.Delete()
                    isActionPerformed = True
                    Exit For
                End If
            End If
        Next
        Return isActionPerformed
    End Function 

如果需要在暫停后恢復打印，則應使用：

  Public Shared Function ResumePrintJob(printerName As String, printJobID As Integer) As Boolean
        Dim isActionPerformed As Boolean = False
        Dim searchQuery As String = "SELECT * FROM Win32_PrintJob"
        Dim searchPrintJobs As New ManagementObjectSearcher(searchQuery)
        Dim prntJobCollection As ManagementObjectCollection = searchPrintJobs.[Get]()
        For Each prntJob As ManagementObject In prntJobCollection
            Dim jobName As System.String = prntJob.Properties("Name").Value.ToString()
            Dim splitArr As Char() = New Char(0) {}
            splitArr(0) = Convert.ToChar(",")
            Dim prnterName As String = jobName.Split(splitArr)(0)
            Dim prntJobID As Integer = Convert.ToInt32(jobName.Split(splitArr)(1))
            Dim documentName As String = prntJob.Properties("Document").Value.ToString()
            If [String].Compare(prnterName, printerName, True) = 0 Then
                If prntJobID = printJobID Then
                    prntJob.InvokeMethod("Resume", Nothing)
                    isActionPerformed = True
                    Exit For
                End If
            End If
        Next
        Return isActionPerformed
    End Function