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Custom Event Handlers

, 11 Apr 2007
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Improved custom implementation of event handling mechanism in c#

Introduction

I found it useful to use custom EventHandlers instead of framework's EventHandler and EventHandler<T> delegates.

  1. Often I had a mistake of multiple assigns of same method to delegate what caused problems.
  2. Calling UI thread from different thread is forbidden and problematic in framework and I found on internet nice solution that should be part of Event class for consistency.
  3. I'd like to have nicer event calling mechanism without checking for null .


Solution : class Event.cs .

  • Uses standard framework delegates EventHandler and EventHandler<T> so it can be easy used in interfaces interchangeable with standard events.
  • Exception when duplicate method assign.
  • Automatic using of ISynchronizeInvoke when calling UI thread.
  • Uses standard framework EventArgs ;
  • Serialization support (no attributes to bypass serialization needed)
  • Event class contains also static methods for firing EventHandlers with support of ISynchronizeInvoke for UI firing from different thread. Syntax: Event.Fire(...); Event.SafeFire(...);

Using the code

-Event myEvent = new Event() (uses EventHandler internally) or Event<T> myEvent = new Event<T>() (uses EventHandler<T>)
-assigning via standard += -=
-myEvent.Fire(senderObject) , myEvent.Fire(args,senderObject) and for safe UI firing support myEvent.SafeFire(...
- for usage in interfaces use in class:
       public event EventHandler MyEvent
        {
            add { myEvent+= value; }
            remove { myEvent -= value; }
        }   

 and in interface then standard : event EventHandler MyEvent; 

History

9 May 2007 - Initial release on Code Project.

License

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About the Author

Rene Dohan

Italy Italy
No Biography provided

Comments and Discussions

 
GeneralmyEvent.SafeFire problem Pinmembertvproducer31-Aug-07 3:32 
GeneralUpdated Sample PinmemberSteveC-A99-Jul-07 8:08 
GeneralRe: Updated Sample PinmemberRene Dohan9-Jul-07 11:09 

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