如何知道DLL事件何时触发

Question

I created a dll contain this event handler:

public void tcp1_Data(object sender, Sockets.DataEventArgs e)
{
  Tcp tcp = (Tcp)sender;

  response = "Socket Connection" + tcp.Tag.ToString() + " replied : " + e.Data.ToString();

  tcp.Close();
}

this will fire when server write some thing in socket connection. so by this, I can read the data on socket.

I used this dll in another project. I want to know in my project (that used dll) exactly when server is writing data on socket connection. as you see in tcp1_Data event, I set result into response variable and in main project (that used dll), I checked this variable polling (if response is not null, it means that this event fired). but Its not what I want. I dont want check this variable all the time.

is there any other way?

---

I tried this as @ThorstenDittmar said:

my dll project (its name is ClientSample) contain:

1. TheClassInDLL Class

    public class TheClassInDLL { public event EventHandler<MyEventArgs> DataEventCalled; public void tcp1_Data(object sender, Sockets.DataEventArgs e) { Tcp tcp = (Tcp)sender; // Note: LOCAL variable string myresponse = "Socket Connection" + tcp.Tag.ToString() + " replied : " + e.Data.ToString(); // Call the new event here if (DataEventCalled != null) DataEventCalled(this, new MyEventArgs(myresponse)); tcp.Close(); } // We use this class to pass arguments to the event handler public class MyEventArgs : EventArgs { public MyEventArgs(string response) { this.Response = response; } public string Response { get; private set; } } } 

   1. TCPSample class

   public class TCPSample { Tcp tcp = new Tcp(); tcp.Data += new System.EventHandler

   and in another project that I used above dll:

    public partial class Form1 : Form { private TheClassInDLL myClass; ClientSample.TCPSample t = new ClientSample.TCPSample(); public Form1() { InitializeComponent(); myClass = new TheClassInDLL(); myClass.DataEventCalled += DataEvent; } private void button1_Click(object sender, EventArgs e) { t.newTCP(); } private void DataEvent(object sender, TheClassInDLL.MyEventArgs e) { MessageBox.Show(e.Response); } } 

but It didnt work, DataEvent never happend. Thanks for any helping...

Answer 1

What you wrote here is an event handler that is called when something happens. There must be a class containing this event handler. Instead of writing a global response variable, declare and invoke another event you can subscribe to from outside that class like this:

public class <TheClassInDLL>
{
    public event EventHandler<MyEventArgs> DataEventCalled;

    // SNIP: All the other code that leads to tcp1_Data being called
    ...

    // The event handler that's called by some code in the class
    public void tcp1_Data(object sender, Dart.Sockets.DataEventArgs e)
    {
        Tcp tcp = (Tcp)sender;

        // Note: LOCAL variable
        string myresponse = "Socket Connection" + tcp.Tag.ToString() + " replied : " + e.Data.ToString();

        // Call the new event here
        if (DataEventCalled != null)
            DataEventCalled(this, new MyEventArgs(myresponse));

        tcp.Close();
    }

    // We use this class to pass arguments to the event handler
    public class MyEventArgs : EventArgs
    {
        public MyEventArgs(string response)
        {
            this.Response = response;
        }

        public string Response
        {
            get;
            private set;
        }
    }
}

From the caller, you use it like this:

public class <TheCallingClassOutsideDLL>
{
    private <TheClassInDLL> myClass;

    public TheCallingClassOutsideDLL()
    {
        myClass = new TheClassInDLL();
        myClass.DataEventCalled += DataEvent;
    }

    private void DataEvent(object sender, <TheClassInDLL>.MyEventArgs e)
    {
        Console.WriteLine(e.Response);
    }
}

Of course you need to replace <TheClassInDLL> and <TheCallingClassOutsideDLL> with the real class names! Creating additional classes of course doesn't work!

Answer 2

For that you got to define your own event and raise it when needed... for Example -> In the class where you set the "response" variable define an event

//your custom event
public event EventHandler<CustomEventArgs> MyCustomEvent;

//This will raise your event and notify all who registered
private void RaiseMyCustomEvent(CustomEventArgs e)
{
    var handler = MyCustomEvent;
    if (handler != null)
    {
        handler(this, e);
    }
}

Maybe you will also need CustomEventArgs (used in the example above)

public class CustomEventArgs : EventArgs
{
    public String Message {get;private set;}
    public CustomEventArgs(String message){
        this.Message = message;
    }

}

The class which is using the dll and that wants to get notified needs to register for this event

YourDllClassInstance.MyCustomEvent += OnMyCustomEvent;

public void OnMyCustomEvent(object sender, CustomEventArgs e){
    Console.WriteLine("Event received");
}

That means in your dll class you got to do something like the following when you want to raise the event

response = "blablabla";
RaiseMyCustomEvent(new CustomEventArgs(response);

Is that what you where asking for?