using System.Runtime.InteropServices; // for DllImport [DllImport("sms.dll")] private static extern IntPtr SmsGetPhoneNumber(IntPtr psmsaAddress);  public enum AddressType {        /// Unknown phone number type.        Unknown,        /// International phone number.        International,        /// National phone number.        National,        /// Network-specific phone number.        NetworkSpecific,        /// Subscriber phone number.        Subscriber,        /// Alphanumeric phone number.        Alphanumeric,        /// Abbreviated phone number.        Abbreviated }</P> <P>public struct PhoneAddress {        /// The address type.        public AddressType AddressType;        /// The phone number in string format.        public String Address; }</P> <P>unsafe public static PhoneAddress SIMPhoneNumber() {        PhoneAddress phoneAddress = new PhoneAddress();</P> <P>       Byte[] buffer = new Byte[516];        fixed (byte* pAddr = buffer)        {               IntPtr res = SmsGetPhoneNumber((IntPtr)pAddr);               if (res != IntPtr.Zero)                      throw new Exception("Could not get phone number from SIM");</P> <P>              byte* pCurrent = pAddr;               phoneAddress.AddressType = (AddressType)Marshal.ReadInt32((IntPtr)pCurrent);               pCurrent += Marshal.SizeOf(phoneAddress.AddressType);               phoneAddress.Address = Marshal.PtrToStringUni((IntPtr)pCurrent);         }                return phoneAddress; }