My question involves events and where I am triggering the events in my class. This class wraps my TCP functionality and I am using TcpListener to achieve this. I realize some TCP stuff may be missing from the following example but I want to make things as simple as possible:
c# 2.0 sample
class MyTcpClass
{
public delegate void ClientConnectHandler(Socket client, int clientNum);
public event ClientConnectHandler ClientConnect;
private Socket wellKnownSocket;
private Socket[] clientSockets = new Socket[MAX_CLIENTS];
private int numConnected = 0;
private void OnClientConnect(Socket client, int clientNum)
{
if (ClientConnect != null)
ClientConnect(client, clientNum);
}
public void StartListening()
{
//initialize wellKnownSocket
//...
wellKnownSocket.BeginAccept(new AsyncCallback(internal_clientConnect);
}
public void internal_clientConnect(IAsyncResult ar)
{
//Add client socket to clientSocket[numConnected]
//numConnected++;
//...
wellKnownSocket.EndAccept(ar);
OnClientConnect(clientSocket[numConnected], numConnected);
//error: event happens on different thread!!
}
}
class MainForm
{
void Button_click()
{
MyTcpClass mtc = new MyTcpClass();
mtc.ClientConnect += mtc_ClientConnected;
}
void mtc_clientConnected(Socket client, int clientNum)
{
ActivityListBox.Items.Add("Client #" + clientNum.ToString() + " connected.");
//exception: cannot modify control on seperate thread
}
}
I guess my question is, without breaking this pattern too much, what makes more sense? Also, if anyone has a better more elegant solution they are welcome.
Theory
class MainForm
{
public MainForm()
{
MyTcpClass mtc = new MyTcpClass();
MyTcpClass2 mtc2 = new MyTcpClass2(this);
//this version holds a Form handle to invoke the event
mtc.ClientConnect += mtc_uglyClientConnect;
mtc2.ClientConnect += mtc2_smartClientConnect;
}
//This event is being called in the AsyncCallback of MyTcpClass
//the main form handles invoking the control, I want to avoid this
void mtc_uglyClientConnect(Socket s, int n)
{
if (mycontrol.InvokeRequired)
{
//call begininvoke to update mycontrol
}
else
{
mycontrol.text = "Client " + n.ToString() + " connected.";
}
}
//This is slightly cleaner, as it is triggered in MyTcpClass2 by using its
//passed in Form handle's BeginInvoke to trigger the event on its own thread.
//However, I also want to avoid this because referencing a form in a seperate class
//while having it (the main form) observe events in the class as well seems... bad
void mtc2_smartClientConnect(Socket s, int n)
{
mycontrol.text = "Client " + n.ToString() + " connected.";
}
}