Closing event for socket

[Helmut Gardner]

Hi folks

is it possible to let VB.NET call a specific handler, when a socket gets closed (either as a server, or as a client)

Thank
Helmut

[Dan Koster]

I think you're asking how to detect when a socket is closed remoteley. I banged my head against that one for quite a while. It's documented very poorly. If that's what you're looking for, this should help.

This snippet is in C# but you should be able to convert it. There's a lot left out so e-mail me if you have any questions

/// code above here ommitte

//continuously poll for incoming messages on this connectio
while(userIsLog edIn

//wait for the connection's mutex to come fre
con.Mtx.WaitOne ()
Debug.WriteLine (" Locked " + con.Name, "CommThread ")

//poll the socket for incoming data (1 second timeout
if(con.Sock.Pol l(1000, SelectMode.Sele ctRead)

if(con.Ns.DataA vailable

//read the incoming dat
numBytes = con.Sock.Receiv e(peekBytes,Soc ketFlags.Peek)
bytes = new byte[numBytes]
con.Ns.Read(byt es, 0, Convert.ToInt32 (bytes.Length))

//throw the event (the event determines what to do with the message
this.OnIncoming Message(this, new MessageEventArg s(bytes, con))

else //client is probably disconnecting

//test for remote disconnection
byte [] buffer = new byte[1];
if(con.Sock.Rec eive(buffer, SocketFlags.Pee k) <= 0)

//no data recieved: this IS a disconnection so throw the even
this.OnRemoteDi sconnection(thi s, new ConnectionEvent Args(con))

//break out of the loop to cause a full local disconnectio
break

els

noData = true
/// code below here ommitted

[Dan Koster]

I think you're asking how to detect when a socket is closed remoteley. I banged my head against that one for quite a while. It's documented very poorly. If that's what you're looking for, this should help.

This snippet is in C# but you should be able to convert it. There's a lot left out so e-mail me if you have any questions

/// code above here ommitte

//continuously poll for incoming messages on this connectio
while(userIsLog edIn

//wait for the connection's mutex to come fre
con.Mtx.WaitOne ()
Debug.WriteLine (" Locked " + con.Name, "CommThread ")

//poll the socket for incoming data (1 second timeout
if(con.Sock.Pol l(1000, SelectMode.Sele ctRead)

if(con.Ns.DataA vailable

//read the incoming dat
numBytes = con.Sock.Receiv e(peekBytes,Soc ketFlags.Peek)
bytes = new byte[numBytes]
con.Ns.Read(byt es, 0, Convert.ToInt32 (bytes.Length))

//throw the event (the event determines what to do with the message
this.OnIncoming Message(this, new MessageEventArg s(bytes, con))

else //client is probably disconnecting

//test for remote disconnection
byte [] buffer = new byte[1];
if(con.Sock.Rec eive(buffer, SocketFlags.Pee k) <= 0)

//no data recieved: this IS a disconnection so throw the even
this.OnRemoteDi sconnection(thi s, new ConnectionEvent Args(con))

//break out of the loop to cause a full local disconnectio
break

els

noData = true
/// code below here ommitted

[Andrey Zvyagilskiy[MSFT]]

If you are using synchronous mode then there are no "perfect" solution,
because there are no separate thread where your handler can be called. If
you are using asynchronous sockets (that you probably should) as soon as
socket will be closed "read handler" will be called and EndReceive will
throw exception when you will call it.

[Andrey Zvyagilskiy[MSFT]]

If you are using synchronous mode then there are no "perfect" solution,
because there are no separate thread where your handler can be called. If
you are using asynchronous sockets (that you probably should) as soon as
socket will be closed "read handler" will be called and EndReceive will
throw exception when you will call it.