parameter less constructor error

Question

I'm trying to make my client subscribe to events that happen on my server.

I have an interface that looks like this:

public delegate void RemoteEventHandler(object sender, ClientEventArgs args);


[Serializable]
public class ClientEventArgs : EventArgs
{
    public ClientEventArgs()
    { }

    public ClientEventArgs(Client _client)
    {
        MyClient = _client;
    }
    public Client MyClient { get; set; }
}

public interface IMonitor
{
    event RemoteEventHandler RemoteEvent;
}

My Server Class looks like this:

public class ConnectionManager : MarshalByRefObject, IMonitor
{
    public event RemoteEventHandler RemoteEvent;

    // call the below code when th event should fire.
     if (RemoteEvent != null)
            RemoteEvent(this, new ClientEventArgs(e.MyClient));
}

Then To set my channels up on the server I do this:

BinaryServerFormatterSinkProvider provider = new BinaryServerFormatterSinkProvider();
provider.TypeFilterLevel = TypeFilterLevel.Full;
IDictionary props = new Hashtable();
props["port"] = 5001;
TcpChannel channel = new TcpChannel(props, null, provider);
ChannelServices.RegisterChannel(channel, false);
RemotingConfiguration.RegisterWellKnownServiceType(
typeof(ConnectionManager),
ConnectionManager",
WellKnownObjectMode.Singleton);

And On the client to set the channels up and subscribe to the event:

TcpChannel channel = new TcpChannel();
        ChannelServices.RegisterChannel(channel, false);
        _monitorObject = (IMonitor)Activator.GetObject(
            typeof(IMonitor),
            "tcp://localhost:5001/ConnectionManager");

_monitorObject.RemoteEvent += _monitorObject_RemoteEvent;

Can anyone explain where this is going wrong please?

Exception:

System.MissingMethodException was unhandled HResult=-2146233069 Message=No parameterless constructor defined for this object.
Source=mscorlib

Imperturbation

Does the exception have an inner exception? – Exhort

It's failing to load the main assembly or one of its dependencies? – Imperturbation

Then you probably are missing a referenced assembly. Did you only copy the exe? – Exhort

After fixing the reference, im getting a no parameter less constructor error? – Imperturbation

You provided a nice stack trace, but not the actual exception... – Altaf

@BenVoigt The stack trace has been replaced by the exception. – Imperturbation

Answer 1

To answer your last question: when using Serializable you need a constructor without parameters. So this one would definitely fail:

[Serializable]
public class ClientEventArgs : EventArgs
{
    public ClientEventArgs(Client _client)
    {
        MyClient = _client;
    }
    public Client MyClient { get; set; }
}

You need to add a parameterless constructor:

[Serializable]
public class ClientEventArgs : EventArgs
{
    public ClientEventArgs()
    { }

    public ClientEventArgs(Client _client)
    {
        MyClient = _client;
    }
    public Client MyClient { get; set; }
}

Exhort

thanks for your response, after rebuilding its still throwing the same error though. – Imperturbation

Are you sure there are no other places with this problem? Maybe the Exception will tell the failing class? – Exhort

The only reference to [Serializable] is in the class from above. Thanks for your patience ! – Imperturbation

And what about your Client class. It is referenced in the EventArgs. – Exhort

I've changed that object to type string, do I need to add anything else if ive done that? – Imperturbation

Not as far as I can see. Give it a try. – Exhort

let us continue this discussion in chat – Imperturbation

Answer 2

My money is on your ConnectionManager class not having a default / parameterless constructor. The remoting infrastructure needs to be able to create an instance of it on the server end.

Sensate

Thanks for this, it compiles, the event never fires but at least it compiles! – Imperturbation