C#实现检测打印机状态(包括打印机是否缺纸、打印队列任务数)
最近工作中碰到一个需求，用户要求需要连续打印8000多张处方用于存档，但是考虑到程序发送文档到打印队列的速度远远大于打印机打印的速度，需要控制程序发送文档到打印队列的速度，这就需要检测打印机打印队列中的任务数，超过一定的任务数就停止发送，低于一定数量继续发送。同时，还得检测是否缺纸，用于提示用户。本文中的代码在惠普打印机中测试通过，废话不多说，直接上代码，相信你一定能看懂的。
方式1：使用Win32 API（我采用的方式）
其中
方法 public static int GetTaskNumber()是检测打印队列中的任务数
方法public static int GetPrinterStatusCodeInt()是检测打印机的状态码
#region 方式1
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
private static extern bool OpenPrinter(string pPrinterName, out IntPtr hPrinter, IntPtr pDefault);
[DllImport("winspool.drv", SetLastError = true)]
private static extern bool ClosePrinter(IntPtr hPrinter);
[DllImport("winspool.drv", SetLastError = true)]
private static extern bool GetPrinter(IntPtr hPrinter,
int dwLevel, IntPtr pPrinter, int cbBuf, out int pcbNeeded);
[DllImport("winspool.drv", CharSet = CharSet.Auto)]
public static extern int EnumJobs(IntPtr hPrinter, int FirstJob, int NoJobs, int Level, IntPtr pInfo, int cdBuf,
out int pcbNeeded, out int pcReturned);
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct PRINTER_INFO_2
{
public string pServerName;
public string pPrinterName;
public string pShareName;
public string pPortName;
public string pDriverName;
public string pComment;
public string pLocation;
public IntPtr pDevMode;
public string pSepFile;
public string pPrintProcessor;
public string pDatatype;
public string pParameters;
public IntPtr pSecurityDescriptor;
public uint Attributes;
public uint Priority;
public uint DefaultPriority;
public uint StartTime;
public uint UntilTime;
public uint Status;
public uint cJobs;
public uint AveragePPM;
}
///
/// 默认打印机的名称
///
private static string printerName = new LocalPrintServer().DefaultPrintQueue.Name;
///
/// 获取打印机的状态编码(方式1)
///
///
/// 检查打印机是否可用(方式1)
///
///
///
/// 获取打印机的状态信息(方式1)
///
///
/// 获取打印机正在打印的任务数(方式1)
///
/// 方式2：使用LocalPrintServer
不过有一点需要注意的是，如果需要实时检测打印机的状态，每次检测状态码，都需要重新new LocalPrintServer对象，不然检测不到新的状态信息
#region 方式2
///
/// 获取打印机的状态编码(方式2)
///
///
/// 检查打印机是否可用(方式2)
///
/// 打印机状态编码
///
/// 获取打印机的状态信息(方式2)
///
/// 打印机状态编码
///
/// 获取打印队列的任务数(方式2)
///
/// 完整代码如下：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Management;
using System.Printing;
using System.Runtime.InteropServices;
using System.Text;
namespace iih.mp.dg.presbatchprint2.bp
{
///
/// 打印机状态帮助类
///
public class PrinterHelper
{
#region 方式1
[DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
private static extern bool OpenPrinter(string pPrinterName, out IntPtr hPrinter, IntPtr pDefault);
[DllImport("winspool.drv", SetLastError = true)]
private static extern bool ClosePrinter(IntPtr hPrinter);
[DllImport("winspool.drv", SetLastError = true)]
private static extern bool GetPrinter(IntPtr hPrinter,
int dwLevel, IntPtr pPrinter, int cbBuf, out int pcbNeeded);
[DllImport("winspool.drv", CharSet = CharSet.Auto)]
public static extern int EnumJobs(IntPtr hPrinter, int FirstJob, int NoJobs, int Level, IntPtr pInfo, int cdBuf,
out int pcbNeeded, out int pcReturned);
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Ansi)]
public struct PRINTER_INFO_2
{
public string pServerName;
public string pPrinterName;
public string pShareName;
public string pPortName;
public string pDriverName;
public string pComment;
public string pLocation;
public IntPtr pDevMode;
public string pSepFile;
public string pPrintProcessor;
public string pDatatype;
public string pParameters;
public IntPtr pSecurityDescriptor;
public uint Attributes;
public uint Priority;
public uint DefaultPriority;
public uint StartTime;
public uint UntilTime;
public uint Status;
public uint cJobs;
public uint AveragePPM;
}
///
/// 默认打印机的名称
///
private static string printerName = new LocalPrintServer().DefaultPrintQueue.Name;
///
/// 获取打印机的状态编码(方式1)
///
///
/// 检查打印机是否可用(方式1)
///
///
///
/// 获取打印机的状态信息(方式1)
///
///
/// 获取打印机正在打印的任务数(方式1)
///
///
/// 获取打印机的状态编码(方式2)
///
///
/// 检查打印机是否可用(方式2)
///
/// 打印机状态编码
///
/// 获取打印机的状态信息(方式2)
///
/// 打印机状态编码
///
/// 获取打印队列的任务数(方式2)
///
///