[英]Prevent User from Printing
我已经在.net中创建了一个应用程序,以使用以下参考资料中的DLL来监视打印机中的作业:
我的问题是:在每天打印5次之后,如何延迟或阻止用户打印?
知道打印作业将保存在数据库中。
感谢您的帮助。
可以使用FindFirstPrinterChangeNotification函数编写一个相当简单的程序,该函数监视用户可用的所有打印机。 它应注意PRINTER_CHANGE_ADD_JOB
事件,该事件指示已开始打印作业。 一旦用户超出标准,您的程序便会删除该用户启动的所有新打印作业。 我认为最好通知用户,而不是仅静默删除其打印作业。
这不会阻止用户尝试打印,但是最终结果相同。 在您的应用程序允许之前,不会产生纸张。
解决了 ! 我使用以下方法来解决我的问题:
暂停打印机作业,请致电:
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
为了取消打印机作业,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
如果需要在暂停后恢复打印,则应使用:
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
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