Why is not this simple example working


T

Tony Johansson

Hello!

I just trying to learn how asp.net is handling html server control.
Normally I have used webbserver control here.
In this example I have dragged a html input button into the page see below.
I have then created an event handling method on the client named
Button1_onclick.
Then I added runat="server" making the ASP.NET to look for control if it
need
any server-side processing.
As the last thing I added an event handler for the html server control in
the code-behind file.

Now to my question when I now run the page and hit the button
no event handler is called. But two event handler should have been called
the one on the client which is called Button1_onclick and the one on the
server
which is called Button1_ServerClick.
So is it not possible do do what I have done here ?


<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs"
Inherits="_Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
<title>Untitled Page</title>
<script language="javascript" type="text/javascript">
<!--

function Button1_onclick()
{
document.write('Now event handler on client is called');
}

// -->
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
&nbsp;
<input id="Button1" runat="server" style="z-index: 102; left: 116px;
position: absolute; top: 368px"
type="button" value="button" language="javascript"
onclick="return Button1_onclick()" onserverclick="Button1_ServerClick" />

</div>
</form>
</body>
</html>

Code-behind file
****************
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
protected void Button1_ServerClick(object sender, EventArgs e)
{
Response.Write("Now event handler on server is called");
}
}

//Tony
 
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B

bruce barker

<input type="button"> does not do a postback, its for client javascript
(no need to cancel postbacks). you probably want type="submit".

-- bruce (sqlwork.com)
 
T

Tony Johansson

But if it's for client javascript why is not
the event handler on the client called.

//Tony
 
R

Ralph

Mark Rae said:
Haven't you already asked this question...? Anyway, make the following
changes and all will be well...


Remove the language="javascript" tag, as that has been deprecated for more
than fourteen years.



Change that to: alert('Hello from the client');
Not absolutely necessary, but try to avoid writing directly to the page in
ASP.NET.
I believe that is for more than just .net.
Apparently some antivirus software will block document.write calls.
 
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T

Tony Johansson

Yes it worked if I follow you instructions. Both the client event handler
and the server event handler was called.
First the client and then the server.

But if I for example used this message document.write('Now event handler on
client is called');
in the client event handler insted of this message alert('Hello from the
client');
then the server event handler was not called for some reason.

Can you give a explanation why the server event handler was not called if I
just used
this message document.write('Now event handler on client is called'); insted
of
this message alert('Hello from the client'); ??

//Tony
 

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