How does one access a control from a static method?

Question

I have an application in C# .NET which has a MainForm and a few classes.

One of these classes receives incoming data messages from a network. I need to

Answer 1

To continue the way you've been doing it, your "TheIncomingDataClass" should have a reference to the MainForm object with which it should interface. When you create an instance of this class (presumably from an instance method of MainForm), you will need to pass in a reference to this MainForm object.

class TheIncomingDataClass{
    MainForm form;

    public TheIncomingDataClass(MainForm form){
        this.form = form;
    }
}

class MainForm : Form{
    MainForm(){
        new TheIncomingDataClass(this);
    }
}

However, as suggested by Bugs, you probably would be better off making this an event on TheIncomingDataClass and subscribing to it from MainForm.

class IncomingMessageEventArgs : EventArgs{
    IncomingMessageType message;

    public IncomingMessageType Message{get{return message;}}

    public IncomingMessageEventArgs(IncomingMessageType message){
        this.message = message;
    }
}

class TheIncomingDataClass{
    public event EventHandler MessageReceived;

    protected virtual void OnMessageReceived(IncomingMessageEventArgs e){
        if(MessageReceived != null)
            MessageReceived(this, e);
    }

    public void IncomingMessage(IncomingMessageType message){
        OnMessageReceived(new IncomingMessageEventArgs(message));
    }
}

class MainForm : Form{
    MainForm(){
        new TheIncomingDataClass().MessageReceived +=
            (s, e)=>txtDisplayMessages.AppendText(e.Message.ToString());
    }
}