Hi,

I have converted a couple of C++ structures to C#.

/*
typedef ULONGLONG BTH_ADDR;
typedef struct _BLUETOOTH_ADDRESS {
   union {
       BTH_ADDR ullLong; // easier to compare again BLUETOOTH_NULL_ADDRESS
       BYTE rgBytes[ 6 ]; // easier to format when broken out
   };
} BLUETOOTH_ADDRESS_STRUCT;
#define BLUETOOTH_ADDRESS BLUETOOTH_ADDRESS_STRUCT
#define BLUETOOTH_NULL_ADDRESS ( (ULONGLONG) 0x0 )
*/

[StructLayout(LayoutKind.Explicit)]
internal struct BluetoothAddress
{
   [MarshalAs(UnmanagedType.U8)]
   [FieldOffset(0)] internal ulong ullLong;
   [MarshalAs(UnmanagedType.ByValArray, SizeConst=6)]
   [FieldOffset(0)] internal byte[] rgBytes;

   internal static BluetoothAddress Create()
   {
       BluetoothAddress ba = new BluetoothAddress();
       ba.ullLong = 0;
       ba.rgBytes = new byte[6];
       return ba;
   }
}

/*
typedef struct
{
   DWORD dwSize;
   BLUETOOTH_ADDRESS address;
   WCHAR szName[BLUETOOTH_MAX_NAME_SIZE];
   ULONG ulClassofDevice;
   USHORT lmpSubversion;
   USHORT manufacturer;
} BLUETOOTH_RADIO_INFO;
*/

[StructLayout(LayoutKind.Sequential)]
internal struct BluetoothRadioInfo
{
   [MarshalAs(UnmanagedType.U4)]
   internal uint dwSize;
   BluetoothAddress address;
   [MarshalAs(UnmanagedType.ByValArray, SizeConst = 32)]
   char[] szName;
   ulong ulClassofDevice;
   ushort lmpSubversion;
   ushort manufacturer;

   internal static BluetoothRadioInfo Create()
   {
       BluetoothRadioInfo bri = new BluetoothRadioInfo();
       bri.address = BluetoothAddress.Create();
       bri.dwSize = (uint)Marshal.SizeOf(typeof(BluetoothRadioInfo));
       bri.szName = new char[32];
       return bri;
   }
}

However, when I use these in the function, I get an error.

public void SomeFunction()
{
   BluetoothRadioInfo bri = BluetoothRadioInfo.Create();
   int retCode = BluetoothGetRadioInfo(phRadio, ref bri);
}

The execution doesn't even come to the above function. When I run the app, I
straight away get the following error:

/*##################################################################################
An unhandled exception of type 'System.TypeLoadException' occurred in
System.Net.Bluetooth.exe

Additional information: Could not load type
System.Net.Bluetooth.BluetoothAddress from assembly System.Net.Bluetooth,
Version=1.0.1787.22198, Culture=neutral, PublicKeyToken=null because it
contains an object field at offset 0 that is incorrectly aligned or
overlapped by a non-object field.
##################################################################################*/

If I change the BluetoothAddress structure to
[StructLayout(LayoutKind.Sequential)], I get error with the function saying
"The dwSize member of the BLUETOOTH_RADIO_INFO structure pointed to by
pRadioInfo is invalid."

I feel I'm doing something wrong with the union structure BluetoothAddress.
Can someone help me please?

TIA.

B Vidyadhar Joshi.