trouble with IPAddress class

Question

I am ripping my hair out on this one. The constructor for this class accepts an argument of byte[]: public IPAddress(byte[]); It will not accept a byte array. Even if I do the following it throws an exception. //assume ipa is an instance of IPAddress byte[] a = ipa.GetAddressBytes(); ipa = new IPAddress(a); It throws an exception i have tried manually creating a byte array with 1234and 5 elements. They all cause an exception. It compiles fine no arguments until you reach this point at runtime and it throws an exception. Please help! -pfoh

shimtanny · Answer

Hi I used Reflector (google for it its free) to have a look on the .net framework code. I think you could use the constructor IPAddress(long address) for an easy use. Therefore you have to make a conversion between bytes and long and reverse. public static byte[] GetBytes(long l) { byte[] b = new byte[4]; b[0] = (byte) ((l) >> 0); b[1] = (byte) ((l) >> 8); b[2] = (byte) ((l) >> 16); b[3] = (byte) ((l) >> 24); return b; } public static long GetLong(byte[] b) { long l = 0; if (b.Length != 4) { throw new ArgumentException(Length of byte array has to be 4. b); } long tmp = 0; tmp = b[0] << 0; l |= tmp; tmp = b[1] << 8; l |= tmp; tmp = b[2] << 16; l |= tmp; tmp = b[3] << 24; l |= tmp; return l; } Maybe i helped. Simon

jonas.pfoh · Answer

Thanks for the info! How did you find the implementation of the constructor? Can I simply find it and open it in VS.net? Also any suggestions on how I should go forth. I want to scan a range of addresses. My initial thought was to extract the address as byte[] increment the last byte then put the array back in the object. Can anyone think of a simpler way to do this? -pfoh

shimtanny · Answer

Hi It's really tricky and MSDN says not a word about it... The constructor IPAddress(byte[] address) expects an ip address V6 in a byte sequence. So the expected length of the array is 16. I had a look on the IPAddress code... // Constructor you called. public IPAddress(byte[] address) : this(address (long) 0) { } public IPAddress(byte[] address long scopeid) { this.m_Family = AddressFamily.InterNetwork; this.m_Numbers = new ushort[8]; this.m_ScopeId = 0; this.m_HashCode = 0; if (address == null) { throw new ArgumentNullException(address); } if (address.Length != 0x10) { throw new ArgumentException(address); // Here is the exception thrown!! } this.m_Family = AddressFamily.InterNetworkV6; for (int num1 = 0; num1 0xffffffff)) { throw new ArgumentOutOfRangeException(scopeid); } this.m_ScopeId = scopeid; } So i don't know how IPV6 addresses are built... but this explains why your call failed. I know this solves not your problem but gives you a hint. Simon

jonas.pfoh · Answer

I am pretty sure Im using 1.1 this is independant of the version of VS.net im using right? If I have the 1.1 framework installed it should work right? I believe it is just a generic argument exception im at work now so its not in front of me. But I am 99% sure it is a generic ArgumentException. The only futher info I get is address which is the argument variable. Thanks -pfoh

shimtanny · Answer

Hi See: MSDN... http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemnetipaddressclassctortopic1.asp Are you using .net framework V1.0? It seems that this constructor is not implemented. What kind of exception was thrown? Simon