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我的问题涉及到事件以及我在课堂中触发事件的位置。这个类包装我的TCP功能,我使用TcpListener来实现这一点。我知道一些TCP的东西可以从下面的例子中会丢失,但我希望把事情尽量简单:从c中的AsyncCallback触发事件#
C#2.0样本
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
}
}
我想我的问题是,没有过多打破这种格局很多,什么更有意义?此外,如果有人有更好的更优雅的解决方案,他们是受欢迎的。
理论
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.";
}
}
所以,你建议第一个例子,我在哪里访问任何winform控件在MainForm使用调用事件处理程序的东西?我意识到MyTcpClass应该忽略它所在的线程,但MyTcpClass与您的客户端连接具有“具有”异步回调关系。我倾向于在线程中触发事件(忽略了哪个线程),MyTcpClass被创建。我看到你的观点并同意它,但是微软自己通过其带有progresschanged事件的“backgroundworker”模拟了一个类似的事件。 – 2010-11-18 14:43:44
@Tom:问题是这个线程模型对于Winforms来说非常特殊 - 你可能甚至无法在创建类的线程上调用事件处理程序! (如果线程终止了怎么办?) – cdhowie 2010-11-18 18:01:10