"steve" <st***@discussions.microsoft.com> wrote in message
news:32**********************************@microsof t.com...
Thanks Truong,
IMHO it's a pity that an event calls the same delegate multiple times. It
would be nice if the delegate was only added once to the list managed by
the
event object.
Regards
Steve
"Truong Hong Thi" wrote:
Hi Steve,
>How many references are stored in the delegate list managed by the
>object.
>eg.
>if I ..
>SomeObject.SomeEvent += TotherObject.SomeEventHandler;
>SomeObject.SomeEvent += TotherObject.SomeEventHandler;
>SomeObject.SomeEvent += TotherObject.SomeEventHandler;
>SomeObject.SomeEvent += TotherObject.SomeEventHandler;
>SomeObject.SomeEvent += TotherObject.SomeEventHandler;
Five. When invoking the even, the five methods will in invoked in the
order you added them.
>And then
>SomeObject.SomeEvent -= TotherObject.SomeEventHandler;
>Will SomeObject.SomeEvent contain a reference to
> >TotherObject.SomeEventHandler
The last TotherObject.SomeEventHandler will be remove. You still have
four!
Regards,
Thi
You can achieve this behavior yourself by overriding the event registration
and unregistration and only adding a particular target once.
private EventHandler myEvt;
public event EventHandler MyEvt
{
add
{
if( myEvt != null )
{
bool found = false;
foreach( EventHandler evt in myEvt )
{
if( evt.Equals(value) )
{
found = true;
break;
}
}
if( !found )
{
myEvt += value;
}
}
}
remove
{
myEvt -= value;
}
}
Caveat: I wrote the code in Outlook Express - but it should give you the
general idea.
Regards
Richard Blewett - DevelopMentor
http://www.dotnetconsult.co.uk/weblog http://www.dotnetconsult.co.uk? 
