Object sender and eventargs E

There is a guy called eventhandler who will tell youProgram), There are some things happening: who caused this? It is caused by an object type object, which is represented by source or sender. What is this? E is the content of things.
As for source and sender, there is no difference. It is the same if you want to use it.
Therefore, the event processing function in the program depends on this implementation: for example, if you click a button, how does the program know which function should be used to process this action? Then the eventhandler guy will tell the program: "button1 (sender) has been clicked (e), please call the corresponding processing function ". Of course, who this function is and what it is to do is written by yourself.
Further, this process is actually: Your action is captured by windows, and Windows sends this action to the program as a system message (you can view the message structure ), the program continuously extracts messages from its own message queue and finds corresponding processing methods in the message loop, in this case, something similar to sender and E in the message structure plays the role of the Bootstrap program to use the correct processing function.
Finally, this sender and E and their entire processing method are just another manifestation of the Windows message mechanism. ^_^
Is C #. net.
Object sender
Data in system. eventargs e object
If the button is used, the sender is the button,
E is an event parameter. In some events, e is of little use. For example, in the mouse event of mouseeventargs, we can see that E includes the coordinates of the mouse for your program.