How to: Create a MessageBox Class for Web Forms.

Question

When I began the programming for http://www.sceptermarketingtechnologies.com, I quickly noticed that Asp.net does not support the MessageBox class that I was familiar with in windows forms.

Since Asp.net runs on the server it doesn't have access to produce a modal dialog box on the client. However, by using a scripting language that runs in the clients browser a similar construct is available. In javascript the window.alert() function will produce a modal dialog similar to what you would expect from MessageBox in windows forms.

So, I decided to create a static class MessageBox with a static method Show(), which will give you the ablility to to still use the syntax MessageBox.Show("Your Message"); and then convert it into the javascript window.alert("Your Message"); and add the script to the end of the current response stream.

I've written a how to on my blog at: http://sceptermt.blogspot.com/2008/02/how-to-create-message-box-class-in-c.html that shows the source code that I used in C# for my web application and details on how it works.

You could also write overloads for the static show() method to allow the class to do a javascript confirm() or a prompt(). I haven't needed that functionality yet so I've just kept it simple.

Answer 1

I give you some code that I found when browsing

  // for postback events

  public static void ShowMessageBox(string _message)

      {

          Page page = HttpContext.Current.Handler as Page;

          page.RegisterStartupScript("key2", "<script>alert('" + _message +  "');</script>");

      }

   

  // for async postback events

   public static void ShowMessageBoxForAsync(string _message)

    {

        Page page = HttpContext.Current.Handler as Page;

        ScriptManager.RegisterClientScriptBlock(page,page.GetType(), "key2", "alert('" + _message + "');", true);

    }

 

// Then you can call this in, let's say , button_click event handler like this ( i assume that your class name is Utilities without any namespace definition) :

protected void myButton_Click(object sender, EventArgs e)

{

Utilities.ShowMessageBox("you entered a wrong password");

}

It achives the same goal