Building a Message Box Class in ASP.NET 2.0

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This is an article on Building a Message Box Class in ASP.NET 2.0 in ASP.NET.
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Introduction



Quite Often, We may wish to inform the user of a successful or an unsuccessful operation in a web form application. An effective way to communicate an important message to the user is through the use a MessageBox or a JavaScript "alert".

The MessageBox class in the System.Windows.Forms namespace is usable only from Windows Forms and NOT ASP.NET Web Forms. In order to alert the user we need to add some client side code into the HTML page. This is a simple task but can become quite annoying if this functionality is required on a regular basis.


Background



Hence, It would be nice if we could simply call a static method from any page that would deal with the client side JavaScript required to display the alert's.

This reusable asset explains about a small MessageBox class with a static Show();
method. This Class can be included in the Project and can be used by simply calling the Show method for displaying a Message Box.

The code



Code: ASP.NET

Code:
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Data.OleDb;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Text;
namespace Message
{
	/// <summary>
	/// Summary description for MessageBox.
	/// </summary>
	public class MessageBox
	{
		private static Hashtable m_executingPages = new Hashtable();
		public MessageBox()
		{
			//
			// TODO: Add constructor logic here
			//
		}
		public static void Show( string sMessage )
		{
			// If this is the first time a page has called this method then
			if( !m_executingPages.Contains( HttpContext.Current.Handler ) )
			{
				// Attempt to cast HttpHandler as a Page.
				Page executingPage = HttpContext.Current.Handler as Page;
				if( executingPage != null )
				{
					// Create a Queue to hold one or more messages.
					Queue messageQueue = new Queue();
					// Add our message to the Queue
					messageQueue.Enqueue( sMessage );
					// Add our message queue to the hash table. Use our page reference
					// (IHttpHandler) as the key.
					m_executingPages.Add( HttpContext.Current.Handler, messageQueue );
					// Wire up Unload event so that we can inject 
					// some JavaScript for the alerts.
					executingPage.Unload += new EventHandler( ExecutingPage_Unload );
				} 
			}
			else
			{
				// If were here then the method has allready been 
				// called from the executing Page.
				// We have allready created a message queue and stored a
				// reference to it in our hastable. 
				Queue queue = (Queue) m_executingPages[ HttpContext.Current.Handler ];
				// Add our message to the Queue
				queue.Enqueue( sMessage );
			}
		}

		// Our page has finished rendering so lets output the
		// JavaScript to produce the alert's
		private static void ExecutingPage_Unload(object sender, EventArgs e)
		{
			// Get our message queue from the hashtable
			Queue queue = (Queue) m_executingPages[ HttpContext.Current.Handler ];
			if( queue != null )
			{
				StringBuilder sb = new StringBuilder();
				// How many messages have been registered?
				int iMsgCount = queue.Count;
				// Use StringBuilder to build up our client slide JavaScript.
				sb.Append( "<script language='javascript'>" );
				// Loop round registered messages
				string sMsg;
				while( iMsgCount-- > 0 )
				{
					sMsg = (string) queue.Dequeue();
					sMsg = sMsg.Replace( "\n", "\\n" );
					sMsg = sMsg.Replace( "\"", "'" );
					sb.Append( @"alert( """ + sMsg + @""" );" );
				}
				// Close our JS
				sb.Append( @"</script>" );
				// Were done, so remove our page reference from the hashtable
				m_executingPages.Remove( HttpContext.Current.Handler );
				// Write the JavaScript to the end of the response stream.
				HttpContext.Current.Response.Write( sb.ToString() );
			}
		}
	}
}



Thanks

blackrubybarb like this
jimh's Avatar, Join Date: Sep 2009
Newbie Member
Hi,

Thanks for allowing me to be a part of this forum. I look forward to becoming an active member.

Jim


naimish like this
naimish's Avatar
Banned
Thanks to shabbir buddy, He's the one
divengrabber's Avatar, Join Date: Aug 2009
Light Poster
thanks for saving my time. I wast lots of time while doing this.
naimish like this
michaelsm's Avatar, Join Date: Aug 2009
Go4Expert Member
Thankyou very much.
shabbir's Avatar, Join Date: Jul 2004
Go4Expert Founder
Nomination for Article of the month - Sep 2009 Started. Nominate this article.
laxsacon's Avatar, Join Date: Oct 2009
Newbie Member
I was registered at your forum. I have printed the test message. Do not delete, please.
rasd123's Avatar
Banned
Thanks to share this information.
joshuab's Avatar, Join Date: Nov 2009
Newbie Member
Hi naimish..

Thanks for your Information...
I have been looking for this answer.
technica's Avatar, Join Date: Dec 2007
CoderByNature
good article. I am going to use this in one of our projects. Thanks for sharing it.