Thread: confused with args for event handler~

howdy~

i'm go my first step on C# on a small asp.net app. i found a tuto very useful and most of its code are neat and nice, but i really get confused on args for even handler, the code of hanlder is somewhawt like this below:

Code:

void EnterBtn_Click(Object Src, EventArgs E) {
            Message.Text = "Hello " + Name.Text + ", welcome to world of ASP.NET£¡";
        }

what about that object and eventargs there ???

thanx~

Thats more of a definition than a real coding issue. A well-formed Event-Handler always has two parameters:

object sender
EventArgs e

Depending on the event it is handling, the handler might receive classes derived from EventArgs like MouseEventArgs for Mouse events or any other class. The object always contains the instance of a class that caused the event. For example if you have a button clicked event, the first parameter given will always be the button in question. This way you can write a single eventhandler for many buttons and still know which one was pressed. The second parameter contains all additional info. For Mouse events, you can get the current mouse coordinates and button states from the second parameter.

thanx nvoigt~

but i also failed when i try to reference Src like this:

Code:

void EnterBtn_Click(Object Src, EventArgs E) {
            Message.Text = "Hello " + Name.Text + ", welcome to world of ASP.NET£¡";
            Src.Text = "fsdfs";
}

what's wrong here ???

While you know that the sender must be a button and therefore have a text, your compiler does not. For the compiler, it is an object and objects don't have a Text property. You have to cast it to a button:

(Sender as Button).Text = ...