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using System;
using System.Web.UI;
using System.Web;
using System.Text;
using System.Collections;
namespace LeeGunn.Web.UI.MessageBox
{
/// <summary>
/// Summary description for MessageBox.
/// </summary>
public class MessageBox
{
private static Hashtable m_executingPages = new Hashtable();
private MessageBox(){}
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() );
}
}
}
}
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