【Silverlight5矢量打印】如何用C#代码检测打印机和驱动是否支持PostScript

Silverlight5支持PostScript矢量打印，矢量打印相比于位图打印速度更快，生成的打印文件更小。SL5默认会采用PS矢量打印，如果打印机不支持，自动切换到位图打印。

虽然微软SL打印组认为PS已经相当普遍，但我想大多数打印机估计并未安装支持PostScript的驱动。HP打印机默认的会是PCL的，估计微软选用PS是学Flash：）

如何用代码检测打印机是否支持PostScript呢？代码如下：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Collections;

using System.Runtime.InteropServices;



namespace PrinterSupportPS

{

    class Program

    {

        static void Main(string[] args)

        {

            string printerName = "Microsoft XPS Document Writer";

            Console.WriteLine(PrinterSupportsPostScript(printerName));

            Console.Read();

        }



        static Int32 GETTECHNOLOGY = 20;

        static Int32 QUERYESCSUPPORT = 8;

        static Int32 POSTSCRIPT_PASSTHROUGH = 4115;

        static Int32 ENCAPSULATED_POSTSCRIPT = 4116;



        static Int32 POSTSCRIPT_IDENTIFY = 4117;

        static Int32 POSTSCRIPT_INJECTION = 4118;

        static Int32 POSTSCRIPT_DATA = 37;

        static Int32 POSTSCRIPT_IGNORE = 38;

        [DllImport("gdi32.dll")]

        static extern int ExtEscape(IntPtr hdc, int nEscape, int cbInput,

           IntPtr lpszInData, int cbOutput, IntPtr lpszOutData);

        [DllImport("gdi32.dll")]

        static extern IntPtr CreateDC(string lpszDriver, string lpszDevice,

           IntPtr lpszOutput, IntPtr lpInitData);

        [DllImport("gdi32.dll")]

        static extern bool DeleteDC(IntPtr hdc);



        static bool PrinterSupportsPostScript(string printername)

        {

            ArrayList PSChecks = new ArrayList();

            PSChecks.Add(POSTSCRIPT_PASSTHROUGH);

            PSChecks.Add(ENCAPSULATED_POSTSCRIPT);

            PSChecks.Add(POSTSCRIPT_IDENTIFY);

            PSChecks.Add(POSTSCRIPT_INJECTION);

            PSChecks.Add(POSTSCRIPT_DATA);

            PSChecks.Add(POSTSCRIPT_IGNORE);



            IntPtr hDC = IntPtr.Zero; ;

            IntPtr BLOB = IntPtr.Zero;



            try

            {

                hDC = CreateDC(null, printername, IntPtr.Zero, IntPtr.Zero);



                int isz = 4;

                BLOB = Marshal.AllocCoTaskMem(isz);

                Marshal.WriteInt32(BLOB, GETTECHNOLOGY);



                int test = ExtEscape(hDC, QUERYESCSUPPORT, 4, BLOB, 0, IntPtr.Zero);

                if (test == 0) return false; // printer driver does not support GETTECHNOLOGY Checks.



                foreach (Int32 val in PSChecks)

                {

                    Marshal.WriteInt32(BLOB, val);

                    test = ExtEscape(hDC, QUERYESCSUPPORT, isz, BLOB, 0, IntPtr.Zero);

                    if (test != 0) return true; // if any of the checks pass, return true

                }

            }

            catch (Exception ex) { Console.WriteLine(ex); }

            finally

            {

                if (hDC != IntPtr.Zero) DeleteDC(hDC);



                if (BLOB != IntPtr.Zero) Marshal.Release(BLOB);

            };



            return false;



        }



    }

}

大家可以建一个控制台程序，用这段代码检测一下。