| 首先我们看看EnumPrinters函数的定义 BOOL EnumPrinters( DWORD Flags, // printer object types LPTSTR Name, // name of printer object DWORD Level, // information level LPBYTE pPrinterEnum, // printer information buffer DWORD cbBuf, // size of printer information buffer LPDWORD pcbNeeded, // bytes received or required LPDWORD pcReturned // number of printers enumerated ); 这个api有几个返回参数, 其中最重要的是pPrinterEnum所指的缓冲区中，是一个 PRINTER_INFO_N的结构数组, 这里N根据Level参数而变化, 这里我们用的是1, 所以用到的结构是 typedef struct _PRINTER_INFO_1 { DWORD Flags; LPTSTR pDescription; LPTSTR pName; LPTSTR pComment; } PRINTER_INFO_1 C#要调用API首先要引入动态库，EnumPrinters在winspool.drv这个动态库中。引入语句如下 [DllImport("winspool.drv", CharSet=CharSet.Auto)] 然后是定义PRINTER_INFO_1结构 [StructLayout(LayoutKind.Sequential, CharSet=CharSet.Auto)] struct PRINTER_INFO_1 { int flags; [MarshalAs(UnmanagedType.LPTStr)] public string pDescription; [MarshalAs(UnmanagedType.LPTStr)] public string pName; [MarshalAs(UnmanagedType.LPTStr)] public string pComment; } 好了，全部的源代码如下： using System; using System.Collections; using System.Runtime.InteropServices; using System.Diagnostics; using System.Drawing.Printing; public class QuickTest { [DllImport("winspool.drv", CharSet=CharSet.Auto)] static extern bool EnumPrinters(int flags, string name, int level, IntPtr pPrinterEnum, int cbBuf, out int pcbNeeded, out int pcReturned); private const int PRINTER_ENUM_NETWORK = 0x00000040; private const int PRINTER_ENUM_LOCAL = 0x00000002; private const int PRINTER_ENUM_REMOTE = 0x00000010; [StructLayout(LayoutKind.Sequential, CharSet=CharSet.Auto)] struct PRINTER_INFO_1 { int flags; [MarshalAs(UnmanagedType.LPTStr)] public string pDescription; [MarshalAs(UnmanagedType.LPTStr)] public string pName; [MarshalAs(UnmanagedType.LPTStr)] public string pComment; } public void EnumeratePrintersWin() { bool Success; int cbRequired; int nEntries; IntPtr outb = IntPtr.Zero; Success = EnumPrinters(PRINTER_ENUM_NETWORK | PRINTER_ENUM_LOCAL | PRINTER_ENUM_REMOTE, null , 1, outb, 0, out cbRequired, out nEntries); outb = Marshal.AllocHGlobal(cbRequired); Success = EnumPrinters(PRINTER_ENUM_NETWORK | PRINTER_ENUM_LOCAL | PRINTER_ENUM_REMOTE, null , 1, outb, cbRequired, out cbRequired, out nEntries); PRINTER_INFO_1[] portsArray = new PRINTER_INFO_1[cbRequired]; IntPtr current = outb; try { for (int i=0; i<portsArray.Length; i++) { portsArray[i] = (PRINTER_INFO_1) Marshal.PtrToStructure(current, typeof(PRINTER_INFO_1)); current=(IntPtr)((int)current+Marshal.SizeOf(typeof(PRINTER_INFO_1))); Console.WriteLine(i+": \n"+portsArray[i].pName+"\n"+portsArray[i].pDescription+"\n"+portsArray[i].pComment+"\n"); } } catch (Exception) { //Console.WriteLine(exp.StackTrace); } Marshal.FreeHGlobal(outb); } public QuickTest () { } public static void Main() { QuickTest qt = new QuickTest(); qt.EnumeratePrintersWin(); } } |
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