In C#, how can I send a binary packet structure with Socket.Send?

Hello,

I am trying to send a binary packet structure using Socket.send. I have defined the packet using "StructLayout" and "FieldOffset" in a manner similar to the following:

[StructLayout(LayoutKind.Explicit, Size = 6)]

public class PacketHdr

{ [FieldOffset(0)]public short PacketType;

[FieldOffset(2)]public int PacketLength; }

After I create an instance of PacketHdr, I need to reference it as "byte [ ]" to send it out using "Socket.Send", since the buffer parameter of Socket.Send is defined as "byte [ ]" as follows:

int Socket.Send(byte [ ] buffer, int offset, int size, ...

How can I reference the packet as "byte [ ]"

This is trivial in C++, but I have not been able to find an example in C#.

Thank you for your help.

Bill Welch

.NET Development32

Hi

Serialize your object to get byte[] using the following code

MemoryStream ms = new MemoryStream();
BinaryFormatter formatter = new BinaryFormatter();
formatter.AssemblyFormat = FormatterAssemblyStyle.Simple;
formatter.TypeFormat = FormatterTypeStyle.TypesWhenNeeded;
formatter.Serialize(ms,<objPacketHdr>);
return ms.GetBuffer(); //THIS WILL RETURN BYTE[] WHICH YOU WANT

Then when you receive this byte[] then Deseiralize it to get actual object,

MemoryStream ms = new MemoryStream(bytes, offset, count); //HERE BYTES IS BYTE[] YOU HAVE RECEIVED
BinaryFormatter formatter = new BinaryFormatter();
formatter.AssemblyFormat = FormatterAssemblyStyle.Simple;
formatter.TypeFormat = FormatterTypeStyle.TypesWhenNeeded;
PacketHdr objPacketHdr = (PacketHdr)formatter.Deserialize(ms);

PLEASE NOTE: You will need to mark your class with [Serializable] attribute to serialize it.

HTH,

include these 2 lines at the top of the class file:

using System.Runtime.Serialization;

using System.Runtime.Serialization.Formatter.Binary;

Here your class goes:

[Serializable]
public class PacketHdr
{
private short packetType;
private int packetLength;

public PacketHdr(short packetType, int packetLength)
{
this.packetType = packetType;
this.packetLength = packetLength;
}
}

Here Function to do the Conversion:

From object to bytes:

private byte[] GetPacketBytes(PacketHdr packetHdr)
{
MemoryStream ms = new MemoryStream();
BinaryFormatter formatter = new BinaryFormatter();
formatter.Serialize(ms, packetHdr);
return ms.ToArray();
}

From Byes to object:

private PacketHdr GetPacketObject(byte[] packetBytes)
{
MemoryStream ms = new MemoryStream();
ms.Write(packetBytes, 0, packetBytes.Length);
ms.Position = 0;
BinaryFormatter formatter = new BinaryFormatter();
return formatter.Deserialize(ms) as PacketHdr;
}

Usage:

PacketHdr p = new PacketHdr(1, 2);

byte[] packetBytes = GetPacketBytes(p); // Write these bytes on Network;

Read the bytes from the Network and contruct the object from the following line:

PacketHdr p1 = GetPacketObject(packetBytes);

Make sure to Receive all the bytes from the Network before you Decerialize bytes back to object otherwise wou;ll get an exception. So you have to make a check that how many bytes are sending and how many bytes you have to receive for a successful deserialization.

I hope this will help.

Best Regards,

Rizwan aka RizwanSharp