C＃多线程委托和事件

Question

I'm having some trouble understanding where to go from here - I have developed a form that has access to a SQL Express database and manipulates it via a DataSet. I have also developed a class that listens on a multi-threaded TCP server for updates from other clients via a proprietary protocol.

What I need to do is get these updates to the form, which has the instance of the dataset to be updated.

I have checked out some of the event and delegate help on here and this guide that seemed handy at first, but suffers from the same problem that a lot of these examples have - they are not very good at articulating exactly what is happening, and end up using similar variables in both classes.

Which class is the "subscriber", and which is the "Publisher"? I really detest forms programming and would do this entirely command-line based, but it is for a group of people who are so computer illiterate that they might experience trauma from having to use a prompt.

Answer 1

The publisher is the object whose class declares the event. For example, a DataTable publishes a RowChanged event.

The object that handles an event is the subscriber. For example, a class with a _table field could subscribe to the RowChanged event thus (assuming the handling method exists, of course):

this._table.RowChanged += this.HandleRowChanged;

Sometimes, a class may subscribe to its own event. An example would be the Load event of a Windows form. This uses more overhead than necessary, and some frameworks provide virtual methods to allow subclasses to extend the base class's functionality without creating an event delegate. That's why the Form's OnLoad method is virtual.