Down/Up Cast for Control Events?

  • Thread starter Thread starter lucius
  • Start date Start date
L

lucius

ASP.NET 2.0

I have web controls with their own event handlers that I need to
funnel into a central handler, eg


TypicalEvent( object sender, TypicalEventArgs e )
{
HandleEverything( sender , (EventArgs)e );
}

LinkEvent( object sender, LinkEventArgs e )
{
HandleEverything( sender , (EventArgs)e );
}

SpecialEvent( object sender, SpecialEventArgs e )
{
HandleEverything( sender , (EventArgs)e );
}


And the central event handler is


HandleEverything( object sender , EventArgs e )
{

}



Within "HandleEverything", I would like to know the original Type of
what is in EventArgs and then cast it to the proper Type, because if
it's TypicalEventArgs there is a Value property, if it is
LinkEventArgs there is an AnchorText property, etc.

How can I use Reflection (or Generics?) to "uncast" and use?

Thanks.
 
Hi lucius,

I assume TypicalEventArgs/LinkEventArgs/SpecialEventArgs are all inherited
(directly or indirectly) from EventArgs. You can always use a child type
where a base type is needed without casting. A child type *is* always a
base type.

To cast a reference with base type to a child type, you need to explicitly
cast it, for example:

TypicalEventArgs e2 = (TypicalEventArgs) e;


Of course you need to determine if it's a TypicalEventArgs first:

if (e is TypicalEventArgs) {
TypicalEvent(sender, (TypicalEventArgs) e);
}


Hope this helps.


Sincerely,
Walter Wang ([email protected], remove 'online.')
Microsoft Online Community Support

==================================================
Get notification to my posts through email? Please refer to
http://msdn.microsoft.com/subscriptions/managednewsgroups/default.aspx#notif
ications. If you are using Outlook Express, please make sure you clear the
check box "Tools/Options/Read: Get 300 headers at a time" to see your reply
promptly.

Note: The MSDN Managed Newsgroup support offering is for non-urgent issues
where an initial response from the community or a Microsoft Support
Engineer within 1 business day is acceptable. Please note that each follow
up response may take approximately 2 business days as the support
professional working with you may need further investigation to reach the
most efficient resolution. The offering is not appropriate for situations
that require urgent, real-time or phone-based interactions or complex
project analysis and dump analysis issues. Issues of this nature are best
handled working with a dedicated Microsoft Support Engineer by contacting
Microsoft Customer Support Services (CSS) at
http://msdn.microsoft.com/subscriptions/support/default.aspx.
==================================================

This posting is provided "AS IS" with no warranties, and confers no rights.
 
Hi lucius,

If you see this, would you please reply here to let me know if you think
this issue is solved now? Thanks.


Regards,
Walter Wang ([email protected], remove 'online.')
Microsoft Online Community Support

==================================================
When responding to posts, please "Reply to Group" via your newsreader so
that others may learn and benefit from your issue.
==================================================

This posting is provided "AS IS" with no warranties, and confers no rights.
 
Back
Top