C#设置默认打印机-COM和WMI二种方式

COM方式：使用Winspool.drv

WMI方式：Class=Win32_ Printer  另注（Powershell中可以 gwmi -Class "Win32_Printer"找到List ）

C#实现

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Management;
using System.Runtime.InteropServices;

namespace MyConsoleApp.Code
{
    /// <summary>
    /// 设置或者获取默认打印机类
    /// </summary>
    public class PrintHelper
    {
        #region DllImport

        [DllImport("Winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
        public static extern bool SetDefaultPrinter(string printerName);

        [DllImport("winspool.drv", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern bool GetDefaultPrinter(StringBuilder pszBuffer, ref int pcchBuffer);

        public static string GetDefaultPrinter()
        {
            const int ERROR_FILE_NOT_FOUND = 2;
            const int ERROR_INSUFFICIENT_BUFFER = 122;
            int pcchBuffer = 0;
            if (GetDefaultPrinter(null, ref pcchBuffer))
            {
                return null;
            }
            int lastWin32Error = Marshal.GetLastWin32Error();
            if (lastWin32Error == ERROR_INSUFFICIENT_BUFFER)
            {
                StringBuilder pszBuffer = new StringBuilder(pcchBuffer);
                if (GetDefaultPrinter(pszBuffer, ref pcchBuffer))
                {
                    return pszBuffer.ToString();
                }
                lastWin32Error = Marshal.GetLastWin32Error();
            }
            if (lastWin32Error == ERROR_FILE_NOT_FOUND)
            {
                return null;
            }
            throw new Exception(Marshal.GetLastWin32Error().ToString());
        }

        #endregion

        #region WMI方式

        private static ManagementObjectSearcher query;
        private static ManagementObjectCollection queryCollection;

        private static ManagementObjectCollection GetManagementObjectCollection(string mql)
        {
            query = new ManagementObjectSearcher(mql);
            return query.Get();
        }

        public static string GetDefaultPrinterByWMI()
        {
            queryCollection = GetManagementObjectCollection("SELECT * FROM Win32_Printer WHERE Default=true");
            if (queryCollection != null)
            {
                foreach (ManagementObject mo in queryCollection)
                {
                    return mo["Name"].ToString();
                }
                return string.Empty;
            }
            else
                return string.Empty;
        }

        public static void SetDefaultPrinterByWMI(string PrinterName)
        {
            queryCollection = GetManagementObjectCollection("SELECT * FROM Win32_Printer");
            if (queryCollection != null && queryCollection.Count > 0)
            {
                foreach (ManagementObject mo in queryCollection)
                {
                    if (string.Compare(mo["Name"].ToString(), PrinterName, true) == 0)
                    {
                        mo.InvokeMethod("SetDefaultPrinter", null);
                        break;
                    }
                }
            }
        }

        #endregion
    }

    /*
     string printName = MyConsoleApp.Code.PrintHelper.GetDefaultPrinterByWMI();
     MyConsoleApp.Code.PrintHelper.SetDefaultPrinterByWMI("Microsoft XPS Document Writer");
     printName = MyConsoleApp.Code.PrintHelper.GetDefaultPrinterByWMI();
     */
}

Powershell 实现

#当前默认打印机
Get-WmiObject -Query "select * from win32_printer where Default=true" ;

#另一种写法，从打印机列表中查找默认
$print=Get-WmiObject -Query "select * from win32_printer" ;
$print|%{if ($_.Default){$_.Name} }

#设置默认的方法
$print[0].SetDefaultPrinter()