c#检查打印机状态

Question

在我的应用程序(Windows 7,VS2010)中,我必须在成功打印图像后减少信用计数器.无论如何,在开始整个过程​​之前,我想了解打印机状态,以便在纸张,卡纸等方面提醒用户.现在,环顾四周我发现了几个使用Windows WMI的例子,但是......从来没有用过.例如,使用THIS代码段,如果我取出纸张,打开封面,打印机状态也随时可用...关闭打印机.

现在打印机状态总是很好,我正在办公室测试在家里舒适关闭的打印机.让我用炸药引爆设备以获得打印机错误状态？

这是我用过的代码

ManagementObjectCollection MgmtCollection;
ManagementObjectSearcher MgmtSearcher;

//Perform the search for printers and return the listing as a collection
MgmtSearcher = new ManagementObjectSearcher("Select * from Win32_Printer");
MgmtCollection = MgmtSearcher.Get();

foreach (ManagementObject objWMI in MgmtCollection)
{

    string name = objWMI["Name"].ToString().ToLower();

    if (name.Equals(printerName.ToLower()))
    {

        int state = Int32.Parse(objWMI["ExtendedPrinterStatus"].ToString());
        if ((state == 1) || //Other
        (state == 2) || //Unknown
        (state == 7) || //Offline
        (state == 9) || //error
        (state == 11) //Not Available
        )
        {
        throw new ApplicationException("hope you are finally offline");
        }

        state = Int32.Parse(objWMI["DetectedErrorState"].ToString());
        if (state != 2) //No error
        {
        throw new ApplicationException("hope you are finally offline");
        }

    }

}

其中'printerName'作为参数被接收.

谢谢你的建议.

Answer 1

你没有说你正在使用的是什么版本的.Net,但是从.Net 3.0开始就有了一些很好的打印功能.我已经使用了这个,虽然我不能确定它报告各种状态级别,我当然看到各种打印机等"Toner Low"等消息.

PrinterDescription是一个自定义类,但您可以看到它使用的属性.

http://msdn.microsoft.com/en-us/library/system.printing.aspx

        PrintQueueCollection printQueues = null;
        List<PrinterDescription> printerDescriptions = null;

        // Get a list of available printers.
        this.printServer = new PrintServer();
        printQueues = this.printServer.GetPrintQueues(new[] { EnumeratedPrintQueueTypes.Local, EnumeratedPrintQueueTypes.Connections });
        printerDescriptions = new List<PrinterDescription>();

        foreach (PrintQueue printQueue in printQueues)
        {
            // The OneNote printer driver causes crashes in 64bit OSes so for now just don't include it.
            // Also redirected printer drivers cause crashes for some printers. Another WPF issue that cannot be worked around.
            if (printQueue.Name.ToUpperInvariant().Contains("ONENOTE") || printQueue.Name.ToUpperInvariant().Contains("REDIRECTED"))
            {
                continue;
            }

            string status = printQueue.QueueStatus.ToString();

            try
            {
                PrinterDescription printerDescription = new PrinterDescription()
                {
                    Name = printQueue.Name,
                    FullName = printQueue.FullName,
                    Status = status == Strings.Printing_PrinterStatus_NoneTxt ? Strings.Printing_PrinterStatus_ReadyTxt : status,
                    ClientPrintSchemaVersion = printQueue.ClientPrintSchemaVersion,
                    DefaultPrintTicket = printQueue.DefaultPrintTicket,
                    PrintCapabilities = printQueue.GetPrintCapabilities(),
                    PrintQueue = printQueue
                };

                printerDescriptions.Add(printerDescription);
            }
            catch (PrintQueueException ex)
            {
                // ... Logging removed
            }
        }

Answer 2

您可以使用上面@mark_h指出的打印机队列来执行此操作。

但是，如果您的打印机不是默认打印机，您需要加载该打印机的队列。您需要做的而不是调用，server.DefaultPrintQueue您需要通过调用加载正确的队列GetPrintQueue()，然后将打印机名称和空字符串数组传递给它。

//Get local print server
var server = new LocalPrintServer();

//Load queue for correct printer
PrintQueue queue = server.GetPrintQueue(PrinterName, new string[0] { }); 

//Check some properties of printQueue    
bool isInError = queue.IsInError;
bool isOutOfPaper = queue.IsOutOfPaper;
bool isOffline = queue.IsOffline;
bool isBusy = queue.IsBusy;

Answer 3

System.Printing命名空间中的PrintQueue类就是您所追求的.它具有许多属性,可提供有关其所代表的打印机状态的有用信息.这里有些例子;

        var server = new LocalPrintServer();

        PrintQueue queue = server.DefaultPrintQueue;

        //various properties of printQueue
        var isOffLine = queue.IsOffline;
        var isPaperJam = queue.IsPaperJammed;
        var requiresUser = queue.NeedUserIntervention;
        var hasPaperProblem = queue.HasPaperProblem;
        var isBusy = queue.IsBusy;

这绝不是一个全面的列表,并且记住队列可能具有一个或多个这些状态,因此您必须考虑处理它们的顺序.