c# - Explain this: CheckBox checkbox = (CheckBox)sender; -

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while going through checkbox found there written 

checkbox checkbox = (checkbox)sender

on checkbox1_checkedchanged event.

please explain means?

the line casts sender checkbox.

why?

the event handler signature checkedchanged event is:

checkchanged(object sender, eventargs e)

so, need cast sender checkbox if want use checkbox specific functionality - object doesn't have can use...

this way checkbox variable can used checkbox id , operate on checkbox.


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