Hello,

what is the meaning of ( object sender, System.EventArgs e )
when they are together as parameters of function of event of
a button, like :
public void rotation_Click(object sender, System.EventArgs e);


Bye,

richard

Under .NET framework, by convention, all events have this format.

The reasoning for the first argument is that a single event handler can be attached to the same event like so.

btnTestA.Click += new EventHandler(btnTest_Click);
btnTestB.Click += new EventHandler(btnTest_Click);

When btnTestA and btnTestB is clicked, the btnTest_Click event handler will be fired. The "object sender" portion will be a reference to whatever one of the buttons was clicked ...

private void btnTest_Click(object sender, EventArgs e)
{
    Button test = sender as Button;

    // etc ...
}

The EventArgs portion is a way to pass extra information to the event handler. In the case above, EventArgs is a base class and no real extra information is passed. However, alot of events use a derivative of EventArgs, which contain extra information.




:
: Hello,
:
: what is the meaning of ( object sender, System.EventArgs e )
: when they are together as parameters of function of event of
: a button, like :
: public void rotation_Click(object sender, System.EventArgs e);
:
:
: Bye,
:
: richard
:
:

This message was edited by richard_u at 2005-11-9 8:35:5

---

Hello,

I do not understand this answer.
I want an easier Explaination.

Bye,

Richard

The "sender" argument is the object that raised the event. The EventArgs argument is extra information passed to the event.

So if u clicked a button, then the sender would be the button that u have clicked.

Plain and simple.

Now the fact that ALL events follow this format is a matter of convention. It is a coding practice / pattern adopted by Mirosoft.

If you do not understand this, then you really must pick up a .NET book, since most devote a full chapter to this topic.

I was looking for the same answer to your question. Maybe this link will help.

http://msdn.microsoft.com/en-us/library/system.eventhandler.aspx