How to make custom event for all SmartParts?

Question

There is C# Project (.NET CF) that uses OpenNETCF.IOC.(UI) library.

Actual situation: In Base Form OnKeyDown event is handled and custom event can be raised (for example if user ESC button pressed). This event can be handled in descendant forms.

After refactoring: Base Form is now container form. All descendant forms are now SmartParts. How should I now raise custom event from container form to SmartParts?

// Base form
private void BaseForm_KeyDown(object sender, KeyEventArgs e)
{
   // Handle ESC button
   if (e.KeyCode == Keys.Escape || e.KeyValue == SomeOtherESCCode)
   {
       this.ButtonESCClicked(sender, new EventArgs());
   }
 }

 // Descendant form
 private void frmMyForm_ButtonESCClicked(object sender, EventArgs e)
 {
     this.AutoValidate = AutoValidate.Disable;
     ...
 }

Answer 1

I'm not sure I fully understand the question, but I'll try to answer. If you want to raise an event from a child class, but that event is defined in a base class, you should use a "helper" method in the base:

public abstract ParentClass : Smartpart
{
    public event EventHandler MyEvent;

    protected void RaiseMyEvent(EventArgs e)
    {
        var handler = MyEvent;
        if(handler != null) handler(this, e);
    }
}

public ChildClass : ParentClass
{
   void Foo()
   {
       // rais an event defined in a parent
       RaiseMyEvent(EventArgs.Empty);
   }
}

If you're trying to go the other way, having the parent notify the children, then it's more like this:

public abstract ParentClass : Smartpart
{
    protected virtual void OnMyEvent(EventArgs e) { } 

   void Foo()
   {
       // something happened, notify any child that wishes to know
       OnMyEvent(EventArgs.Empty);

       // you could optionally raise an event here so others could subscribe, too
   }
}

public ChildClass : ParentClass
{
    protected override void OnMyEvent(EventArgs e)
    {
        // this will get called by the parent/base class 
    }
}