This works:

public event CancelEventHandler PreClick;
...
private void button1_Click(object sender, System.EventArgs e)
{
	CancelEventArgs ce = new CancelEventArgs(true);
	if (PreClick != null)
	{
		PreClick(this, ce);
	}
	if (ce.Cancel == false)
	{
		MessageBox.Show("Parent Code");
		if (PostClick != null)
		{
			PostClick(this, new EventArgs());
		}
	}
}

Then on the form

private void mybutton1_PreClick(object sender, CancelEventArgs e)
{
	e.Cancel = this.checkBox1.Checked;
}

>Dave,
>
>>The standard .net way of doing this is to use the CancelEventArgs class instead of the regular EventArgs class.
>
>Yeah, all well and good for a Closing Event on a form, but I don't think that the Button Click event handles either a CancelEventHandler or CancelEventArgs. Unless I missed something when I tried it.
>
>~~Bonnie
>
>>
>>It adds an additional Cancel property that your base class could process and cancel furthur processing of the event.
>>
>>See http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlrfsystemcomponentmodelcanceleventargsclasstopic.asp
>>
>>>
>>>This works great, but what I'm trying to achieve is to prevent this default parent code
>>>
>>>

>>>        '------------------default code goes here---------------------
>>>        MsgBox("parent click at class level")
>>>        '------------------default code goes here---------------------
>>>

>>>
>>>from running if necessary, or maybe override it. For example something happens in my preclick method and I then decide to abort the action etc.