how to retrieve information of previous fired event

Hi,,
i want to maintain infromation of last fired event in my application, in my project i need to check on which button user clicked and perform opration according to this, but didn't wnat to create any object or set property.  For this I want to do so by using Object Sender... But I didn't know that how it can be used.. please tell me how can I implelmet object sender???
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