WebMsgBox class is a message box for ASP.NET. 

Recently, I needed a Windows MessageBox like class for ASP.NET. Doing some search on Google, I found some code for message box in VB.NET and converted code from VB.NET to C# and made some changes. Unfortunately, I forgot the URL where I found the code. 

WebMsgBox Class

WebMsgBox class represents a message box for ASP.NET applications. This class has a static method Show, which is used to display a message box. The Show method takes a single argument of string type, which is the message you want to display.

using System;

using Microsoft.VisualBasic;

using System.Text;

using System.Collections;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

namespace TestWebMsgApp

{

      public class WebMsgBox

      {

            protected static Hashtable handlerPages = new Hashtable();            

            private WebMsgBox()

            {

            }

            public static void Show(string Message)

            {

                  if (!(handlerPages.Contains(HttpContext.Current.Handler)))

                  {

                        Page currentPage = (Page)HttpContext.Current.Handler;

                        if (!((currentPage == null)))

                        {

                              Queue messageQueue = new Queue();

                              messageQueue.Enqueue(Message);

                              handlerPages.Add(HttpContext.Current.Handler, messageQueue);

                              currentPage.Unload += new EventHandler(CurrentPageUnload);

                        }

                  }

                  else

                  {

                        Queue queue = ((Queue)(handlerPages[HttpContext.Current.Handler]));

                        queue.Enqueue(Message);

                  }

            }

            private static void CurrentPageUnload(object sender, EventArgs e)

            {

                  Queue queue = ((Queue)(handlerPages[HttpContext.Current.Handler]));

                  if (queue != null)

                  {

                        StringBuilder builder = new StringBuilder();

                        int iMsgCount = queue.Count;

                        builder.Append("<script language='javascript'>");

                        string sMsg;

                        while ((iMsgCount > 0))

                        {

                              iMsgCount = iMsgCount - 1;

                              sMsg = System.Convert.ToString(queue.Dequeue());

                              sMsg = sMsg.Replace("\"", "'");

                              builder.Append("alert( \"" + sMsg + "\" );");

                        }

                        builder.Append("</script>");

                        handlerPages.Remove(HttpContext.Current.Handler);

                        HttpContext.Current.Response.Write(builder.ToString());

                  }

            }

      }

} 

How to use WebMsgBox?

Download the attached WebMsgBox.cs and add it to your project. You will have to change the namespace of the class. Change the following line to your project's namespace in WebMsgBox.cs file:

namespace TestWebMsgApp

Now call WebMsgBox.Show method when you need to display a message box. For example, if you want to display a message box on a button click, add the following code to the button click event handler.

WebMsgBox.Show("Your message here");