How Can We Prevent Duplicate Event Handler Invocations During Object Deserialization?

Detecting Event Handler Duplication in Deserialized Objects

When deserializing a list of objects with event handlers into a session state, it's essential to determine if the event handler has already been added to prevent multiple invocations. This issue arises because deserialization may not correctly restore the event handler's association with the object.

One proposed solution is to add the event handler to the Get property accessing the object. While effective, it can lead to unnecessary multiple invocations if the event handler is added every time the object is accessed.

Solution: Safe Unregistering and Reregistering

To address this concern, a more efficient approach is to safely unregister the event handler before reregistering it:

myClass.MyEvent -= MyHandler;
myClass.MyEvent += MyHandler;

This code ensures that the event handler is registered only once, even if it was not previously registered. This practice eliminates the risk of multiple invocations and maintains the desired functionality of the event handler.

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