【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;}}
}