Can someone explains me this code?

Trupti Rane

Button btn = (Button)Sender;

I have come across this code but not getting it.

it will help to learn new thing if someone explains this code and its use.

Thanx in advance.

3 Replies

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Vulpes13y ago
It's possible for several buttons to share the same Click eventhandler.

Once you've added an eventhandler for one button, you'll find that in the Properties Box for other buttons the existing handler can be selected from a drop-down list.

In these cases the 'sender' argument contains a reference to which button was actually clicked.

Exactly the same principle applies to other controls and events.
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Trupti Rane13y ago
Actually i come across this code under button click event like as follows private void btnOne_Click(object sender, EventArgs e) { Button btnNumbers = (Button)sender; if (check == true) { lblScreen.Text = ""; } lblScreen.Text += btnNumbers.Text; check = false; } then this event is use by some other buttons also. can u explain me in this context.
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Ashish Shukla13y ago
Whenever some event occurs,like clicking a button, an eventhandler executes.The event handlers in .NET contains two arguments of type object and EventArgs.object argument which is named sender here represnts the object that fired the event in this case Button.
EventArgs contains additonal event information.
Since the sender is of type object if we want to retreive information from it we need
to typecast it.
Following represnets a typical click event handler method signature

private void ButtonClick(object sender, EventArgs e)

Since in the above scenario it is of type button hence it is cast to Button using (Button)Sender

Please let me know if this answers your question.
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