OnValidating override question

[proxyuser]

Let's say I subclass a control such as TextBox, and I override OnValidating.
The first thing I should do, I think, is call base.OnValidating. Then, I
should check if the base has cancelled? Then, what if I am subclassed? In
other words, when the subclass calls me. Looking for a general strategy for
handling this type of event.

public override void OnValidating(CancelEventArgs e)
{
if (e.Cancel) ?? // subclass has already canceled?

base.OnValidating(e);

if (e.Cancel) ??
}