.NET – 深入系统编程 - Part 1

using System;

using System.Runtime.InteropServices;//  P/Invoke 必需

using System.Text;

namespace DevClasses

{

 /// <summary>

 /// Summary description for Class.

 /// </summary>

 class DeviceClasses

 {

  /// <summary>

  /// The main entry point for the application.

  /// </summary>

  public const int MAX_NAME_PORTS=7;

  public const int RegDisposition_OpenExisting=(0x00000001); 

    // open key only if exists

  public const int CM_REGISTRY_HARDWARE=(0x00000000);

  public const int CR_SUCCESS = (0x00000000);

  public const int CR_NO_SUCH_VALUE = (0x00000025);

  public const int CR_INVALID_DATA = (0x0000001F);

  public const int DIGCF_PRESENT = (0x00000002);

  public const int DIOCR_INSTALLER = (0x00000001);

// MaximumAllowed access type to Reg.

  public const int MAXIMUM_ALLOWED = (0x02000000);

[StructLayout(LayoutKind.Sequential)] //为了保证数据交流顺利  

 public class SP_DEVINFO_DATA  //struct 也可以

 {

 public int cbSize;

 public Guid ClassGuid;

 public int DevInst; // DEVINST handle

 public ulong Reserved;

 };

  //声明函数原型

  [DllImport("cfgmgr32.dll")]

  public static extern UInt32

  CM_Open_DevNode_Key(IntPtr dnDevNode, UInt32 samDesired, 

         UInt32 ulHardwareProfile,

         UInt32 Disposition,IntPtr phkDevice, UInt32 ulFlags);

  [DllImport("cfgmgr32.dll")]

  public static extern UInt32

  CM_Enumerate_Classes(UInt32 ClassIndex,ref Guid ClassGuid, UInt32 Params);

  [DllImport("setupapi.dll")]//

  public static extern Boolean

   SetupDiClassNameFromGuidA(ref Guid ClassGuid,

            StringBuilder ClassName, //char * ?

   UInt32 ClassNameSize, ref UInt32 RequiredSize);

  [DllImport("setupapi.dll")]

  public static extern IntPtr

   SetupDiGetClassDevsA(ref Guid ClassGuid, UInt32 Enumerator,

   IntPtr  hwndParent, UInt32 Flags);

  [DllImport("setupapi.dll")]

  public static extern Boolean

   SetupDiEnumDeviceInfo(IntPtr DeviceInfoSet, UInt32 MemberIndex,

   ref SP_DEVINFO_DATA  DeviceInfoData);

  [DllImport("setupapi.dll")]

  public static extern Boolean

   SetupDiDestroyDeviceInfoList(IntPtr DeviceInfoSet);

  [DllImport("setupapi.dll")]

  public static extern IntPtr

   SetupDiGetClassDevsA(ref Guid ClassGuid, UInt32 samDesired,

   UInt32 Flags, ref string hwndParent, IntPtr Reserved);

  [DllImport("setupapi.dll")]

  public static extern IntPtr

  SetupDiOpenClassRegKeyExA(

  ref Guid ClassGuid, UInt32 samDesired, int Flags, IntPtr MachineName,

  UInt32 Reserved);

  [DllImport("advapi32.dll")]

  public static extern UInt32

  RegQueryValueA(IntPtr KeyClass,UInt32 SubKey,

         StringBuilder ClassDescription,ref UInt32 sizeB);

  [DllImport("user32.dll")]

  public static extern Boolean

  CharToOem(String lpszSrc, StringBuilder lpszDst);

   //遍历

public static int EnumerateClasses(UInt32 ClassIndex, 

   ref StringBuilder ClassName, StringBuilder ClassDescription, 

        ref bool DevicePresent)

  {

   Guid ClassGuid=Guid.Empty;

   IntPtr NewDeviceInfoSet;

   SP_DEVINFO_DATA DeviceInfoData;

   UInt32 result;

   StringBuilder name=new StringBuilder("");

   bool resNam=false;

   UInt32 RequiredSize=0;

   IntPtr ptr;

   result = CM_Enumerate_Classes(ClassIndex, ref ClassGuid,0);

    ClassName=new StringBuilder("");

    DevicePresent=false;

   //incorrect device class:

   if(result == CR_INVALID_DATA)

   {

    return -2;

   }

  //device class is absent

   if(result == CR_NO_SUCH_VALUE)

   {

    return -1;

   }

  //bad param. - fatal error

   if(result != CR_SUCCESS)

   {

    return -3;

   }

   name.Capacity=0;

   resNam=SetupDiClassNameFromGuidA(ref ClassGuid,name,RequiredSize,

         ref RequiredSize);

   if(RequiredSize > 0)

    {

    name.Capacity=(int)RequiredSize;

    resNam=SetupDiClassNameFromGuidA(ref ClassGuid,name,

           RequiredSize,ref RequiredSize);

    }

   NewDeviceInfoSet=SetupDiGetClassDevsA(

    ref ClassGuid,

    0,

    IntPtr.Zero,

    DIGCF_PRESENT);

   if(NewDeviceInfoSet.ToInt32() == -1)

    {  DevicePresent=false;

      ClassName=name;

      return 0;}

   IntPtr KeyClass=SetupDiOpenClassRegKeyExA(

    ref ClassGuid, MAXIMUM_ALLOWED, DIOCR_INSTALLER,IntPtr.Zero,0);

   if(KeyClass.ToInt32() == -1)

    {  DevicePresent=false;

      ClassName=name;

      return 0;}

   UInt32 sizeB=1000;

   String abcd="";

   StringBuilder CD=new StringBuilder("");

   ClassDescription.Capacity=1000;

   UInt32 res=RegQueryValueA(KeyClass,0,ClassDescription,ref sizeB);

   if(res != 0)ClassDescription=new StringBuilder("");

   SetupDiDestroyDeviceInfoList(NewDeviceInfoSet);

    ClassName=name;

    DevicePresent=true;

   return 0;

  }

  [STAThread]

  static void Main(string[] args)

  {

   StringBuilder classes=new StringBuilder("");

   StringBuilder classesDescr=new StringBuilder("");

   StringBuilder classesDescrOEM=new StringBuilder("");

   classesDescrOEM.Capacity=1000;

   Boolean DevExist=false;

   UInt32 i=0;

   while(true)

   {

   int res=EnumerateClasses(i,ref classes,classesDescr,ref DevExist);

   if(res == -1)break;

   ++i;

   if(res < -1 || !DevExist)continue;

   Console.WriteLine("ClassName={0}, Description={1}",classes,classesDescr);

   }

   return;

  }

 }

}