Withevents in c# 1

MadJock · Jan 10, 2004

Folks,

I am working through an ASP.NET book that focusses on vb.net. In order to learn better, I'm trying to convert the examples to C#.

Unfortunately, I've got stuck with event handling and can't find any reference I understand on the web.

The application is a currency converter (simple one!) that uses an aspx file and a cs file.

CS File code:

Code:

using Microsoft.VisualBasic;
using System;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

public class CurrencyConverter : Page {

	protected HtmlGenericControl Result;
	protected HtmlInputButton Convert;
	protected HtmlInputText US;
	protected delegate void MyEvent();

	private void Convert_ServerClick(Object sender, EventArgs e) {
		decimal USAmount = Decimal.Parse(US.Value);
		decimal EuroAmount = (USAmount * (decimal) 1.12);
		Result.InnerText = USAmount.ToString() + &quot; US Dollars = &quot; + EuroAmount.ToString() + &quot; Euros &quot;;
	}

}

ASPX File code:

Code:

<%@ Page Language=&quot;C#&quot; Inherits=&quot;CurrencyConverter&quot; Src=&quot;CurrencyConverter.cs&quot; AutoEventWireup=&quot;False&quot; %>
<html>
<body>
	<form method=&quot;post&quot; runat=&quot;server&quot;>
		<div>
			Convert:  
			<input type=&quot;text&quot; id=&quot;US&quot; runat=&quot;server&quot; />  US Dollars to Euros.
			<br /> <br />
			<input type=&quot;submit&quot; value=&quot;OK&quot; id=&quot;Convert&quot; runat=&quot;server&quot; />
			<div style=&quot;FONT_WEIGHT: bold&quot; id=&quot;Result&quot; runat=&quot;server&quot;></div>
		</div>
	
	</form>
</body>
</html>

The example in VB.NET shows the following two lines which I do not know how to reproduce in c#:

Code:

' It's the WithEvents keyword throwing me here
Protected WithEvents Convert as HtmlInputButton

and

Code:

' it's the handles keyword throwing me here!
Private Sub Convert_ServerClick(blah) Handles Convert.ServerClick

I think I will need to use a delegate in c#, but am unure of what to do with it (you'll see I've declared one in my C# class).

Any advice would be greatly appreciated.

Thanks,

Graeme

website:

http://www.graeme-taylor.co.uk

LOVEYUAN · Jan 10, 2004

You does not need to use a delegate in c#.
The line "protected HtmlInputButton Convert;" in C# is equal to
the line "Protected WithEvents Convert as HtmlInputButton" in VB.NET.

The line "this.Convert.ServerClick += new System.EventHandler(this.Convert_ServerClick);" in C# is equal to
the line "Private Sub Convert_ServerClick(blah) Handles Convert.ServerClick" in VB.NET.

The following code will work.

CurrencyConvert.aspx
<%@ Page language="c#" Codebehind="CurrencyConvert.aspx.cs" AutoEventWireup="false" Inherits="Test.CurrencyConvert" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>CurrencyConvert</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio 7.0">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content="

http://schemas.microsoft.com/intellisense/ie5">

</HEAD>
<body MS_POSITIONING="GridLayout">
<form id="CurrencyConvert" method="post" runat="server">
<div>
Convert: <input type="text" id="US" runat="server" NAME="US"> US Dollars to
Euros.
<br>
<br>
<input type="submit" value="OK" id="Convert" runat="server" NAME="Convert">
<div style="FONT_WEIGHT: bold" id="Result" runat="server"><FONT face="MS UI Gothic"></FONT></div>
</div>
</form>
</body>
</HTML>

CurrencyConvert.aspx.cs

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace Test
{
/// <summary>
///
/// </summary>
public class CurrencyConvert : System.Web.UI.Page
{
protected System.Web.UI.HtmlControls.HtmlInputText US;
protected System.Web.UI.HtmlControls.HtmlInputButton Convert;
protected System.Web.UI.HtmlControls.HtmlGenericControl Result;

private void Page_Load(object sender, System.EventArgs e)
{
}

#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{
//
//
//
InitializeComponent();
base.OnInit(e);
}

/// <summary>
///
///
/// </summary>
private void InitializeComponent()
{
this.Convert.ServerClick += new System.EventHandler(this.Convert_ServerClick);
this.Load += new System.EventHandler(this.Page_Load);

}
#endregion

private void Convert_ServerClick(object sender, System.EventArgs e)
{
decimal USAmount = Decimal.Parse(US.Value);
decimal EuroAmount = (USAmount * (decimal) 1.12);
Result.InnerText = USAmount.ToString() + " US Dollars = " + EuroAmount.ToString() + " Euros ";
}
}
}

MadJock · Jan 11, 2004

LOVEYUAN,

Thank you for code and explanation. That is just what I was after. I think a star is deserved.

Graeme

website:

http://www.graeme-taylor.co.uk

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Withevents in c# 1

MadJock

Programmer

LOVEYUAN

Programmer

MadJock

Programmer

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