Posting tonight’s code, for everybody’s enjoyment:
public class SetupDiWrap
{
static public string ComPortNameFromFriendlyNamePrefix(string friendlyNamePrefix)
{
const string className = "Ports";
Guid[] guids = GetClassGUIDs(className);
System.Text.RegularExpressions.Regex friendlyNameToComPort =
new System.Text.RegularExpressions.Regex(@".? \((COM\d+)\)$"); // "..... (COMxxx)" -> COMxxxx
foreach (Guid guid in guids)
{
// We start at the "root" of the device tree and look for all
// devices that match the interface GUID of a disk
Guid guidClone = guid;
IntPtr h = SetupDiGetClassDevs(ref guidClone, IntPtr.Zero, IntPtr.Zero, DIGCF_PRESENT | DIGCF_PROFILE);
if (h.ToInt32() != INVALID_HANDLE_VALUE)
{
int nDevice = 0;
while (true)
{
SP_DEVINFO_DATA da = new SP_DEVINFO_DATA();
da.cbSize = (uint)Marshal.SizeOf(da);
if (0 == SetupDiEnumDeviceInfo(h, nDevice++, ref da))
break;
uint RegType;
byte[] ptrBuf = new byte[BUFFER_SIZE];
uint RequiredSize;
if (SetupDiGetDeviceRegistryProperty(h, ref da,
(uint)SPDRP.FRIENDLYNAME, out RegType, ptrBuf,
BUFFER_SIZE, out RequiredSize))
{
const int utf16terminatorSize_bytes = 2;
string friendlyName = System.Text.UnicodeEncoding.Unicode.GetString(ptrBuf, 0, (int)RequiredSize - utf16terminatorSize_bytes);
if (!friendlyName.StartsWith(friendlyNamePrefix))
continue;
if (!friendlyNameToComPort.IsMatch(friendlyName))
continue;
return friendlyNameToComPort.Match(friendlyName).Groups[1].Value;
}
} // devices
SetupDiDestroyDeviceInfoList(h);
}
} // class guids
return null;
}
/// <summary>
/// The SP_DEVINFO_DATA structure defines a device instance that is a member of a device information set.
/// </summary>
[StructLayout(LayoutKind.Sequential)]
private struct SP_DEVINFO_DATA
{
/// <summary>Size of the structure, in bytes.</summary>
public uint cbSize;
/// <summary>GUID of the device interface class.</summary>
public Guid ClassGuid;
/// <summary>Handle to this device instance.</summary>
public uint DevInst;
/// <summary>Reserved; do not use.</summary>
public uint Reserved;
}
[StructLayout(LayoutKind.Sequential)]
private struct SP_DEVICE_INTERFACE_DATA
{
public Int32 cbSize;
public Guid interfaceClassGuid;
public Int32 flags;
private UIntPtr reserved;
}
const int BUFFER_SIZE = 1024;
[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
private struct SP_DEVICE_INTERFACE_DETAIL_DATA
{
public int cbSize;
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = BUFFER_SIZE)]
public string DevicePath;
}
private enum SPDRP
{
DEVICEDESC = 0x00000000,
HARDWAREID = 0x00000001,
COMPATIBLEIDS = 0x00000002,
NTDEVICEPATHS = 0x00000003,
SERVICE = 0x00000004,
CONFIGURATION = 0x00000005,
CONFIGURATIONVECTOR = 0x00000006,
CLASS = 0x00000007,
CLASSGUID = 0x00000008,
DRIVER = 0x00000009,
CONFIGFLAGS = 0x0000000A,
MFG = 0x0000000B,
FRIENDLYNAME = 0x0000000C,
LOCATION_INFORMATION = 0x0000000D,
PHYSICAL_DEVICE_OBJECT_NAME = 0x0000000E,
CAPABILITIES = 0x0000000F,
UI_NUMBER = 0x00000010,
UPPERFILTERS = 0x00000011,
LOWERFILTERS = 0x00000012,
MAXIMUM_PROPERTY = 0x00000013,
}
[DllImport("setupapi.dll", SetLastError = true)]
static extern bool SetupDiClassGuidsFromName(string ClassName,
ref Guid ClassGuidArray1stItem, UInt32 ClassGuidArraySize,
out UInt32 RequiredSize);
[DllImport("setupapi.dll")]
internal static extern IntPtr SetupDiGetClassDevsEx(IntPtr ClassGuid,
[MarshalAs(UnmanagedType.LPStr)]String enumerator,
IntPtr hwndParent, Int32 Flags, IntPtr DeviceInfoSet,
[MarshalAs(UnmanagedType.LPStr)]String MachineName, IntPtr Reserved);
[DllImport("setupapi.dll")]
internal static extern Int32 SetupDiDestroyDeviceInfoList(IntPtr DeviceInfoSet);
[DllImport(@"setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern Boolean SetupDiEnumDeviceInterfaces(
IntPtr hDevInfo,
IntPtr optionalCrap, //ref SP_DEVINFO_DATA devInfo,
ref Guid interfaceClassGuid,
UInt32 memberIndex,
ref SP_DEVICE_INTERFACE_DATA deviceInterfaceData
);
[DllImport("setupapi.dll")]
private static extern Int32 SetupDiEnumDeviceInfo(IntPtr DeviceInfoSet,
Int32 MemberIndex, ref SP_DEVINFO_DATA DeviceInterfaceData);
[DllImport("setupapi.dll")]
private static extern Int32 SetupDiClassNameFromGuid(ref Guid ClassGuid,
StringBuilder className, Int32 ClassNameSize, ref Int32 RequiredSize);
[DllImport("setupapi.dll")]
private static extern Int32 SetupDiGetClassDescription(ref Guid ClassGuid,
StringBuilder classDescription, Int32 ClassDescriptionSize, ref Int32 RequiredSize);
[DllImport("setupapi.dll")]
private static extern Int32 SetupDiGetDeviceInstanceId(IntPtr DeviceInfoSet,
ref SP_DEVINFO_DATA DeviceInfoData,
StringBuilder DeviceInstanceId, Int32 DeviceInstanceIdSize, ref Int32 RequiredSize);
[DllImport("setupapi.dll", CharSet = CharSet.Auto)]
static extern IntPtr SetupDiGetClassDevs( // 1st form using a ClassGUID only, with null Enumerator
ref Guid ClassGuid,
IntPtr Enumerator,
IntPtr hwndParent,
int Flags
);
[DllImport(@"setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern Boolean SetupDiGetDeviceInterfaceDetail(
IntPtr hDevInfo,
ref SP_DEVICE_INTERFACE_DATA deviceInterfaceData,
ref SP_DEVICE_INTERFACE_DETAIL_DATA deviceInterfaceDetailData,
UInt32 deviceInterfaceDetailDataSize,
out UInt32 requiredSize,
ref SP_DEVINFO_DATA deviceInfoData
);
/// <summary>
/// The SetupDiGetDeviceRegistryProperty function retrieves the specified device property.
/// This handle is typically returned by the SetupDiGetClassDevs or SetupDiGetClassDevsEx function.
/// </summary>
/// <param Name="DeviceInfoSet">Handle to the device information set that contains the interface and its underlying device.</param>
/// <param Name="DeviceInfoData">Pointer to an SP_DEVINFO_DATA structure that defines the device instance.</param>
/// <param Name="Property">Device property to be retrieved. SEE MSDN</param>
/// <param Name="PropertyRegDataType">Pointer to a variable that receives the registry data Type. This parameter can be NULL.</param>
/// <param Name="PropertyBuffer">Pointer to a buffer that receives the requested device property.</param>
/// <param Name="PropertyBufferSize">Size of the buffer, in bytes.</param>
/// <param Name="RequiredSize">Pointer to a variable that receives the required buffer size, in bytes. This parameter can be NULL.</param>
/// <returns>If the function succeeds, the return value is nonzero.</returns>
[DllImport("setupapi.dll", CharSet = CharSet.Auto, SetLastError = true)]
private static extern bool SetupDiGetDeviceRegistryProperty(
IntPtr DeviceInfoSet,
ref SP_DEVINFO_DATA DeviceInfoData,
uint Property,
out UInt32 PropertyRegDataType,
byte[] PropertyBuffer,
uint PropertyBufferSize,
out UInt32 RequiredSize);
const int DIGCF_DEFAULT = 0x1;
const int DIGCF_PRESENT = 0x2;
const int DIGCF_ALLCLASSES = 0x4;
const int DIGCF_PROFILE = 0x8;
const int DIGCF_DEVICEINTERFACE = 0x10;
const int INVALID_HANDLE_VALUE = -1;
private static Guid[] GetClassGUIDs(string className)
{
UInt32 requiredSize = 0;
Guid[] guidArray = new Guid[1];
bool status = SetupDiClassGuidsFromName(className, ref guidArray[0], 1, out requiredSize);
if (true == status)
{
if (1 < requiredSize)
{
guidArray = new Guid[requiredSize];
SetupDiClassGuidsFromName(className, ref guidArray[0], requiredSize, out requiredSize);
}
}
else
throw new System.ComponentModel.Win32Exception();
return guidArray;
}
}