问题:

I was attempting to add MessageBox.Show(Message); and it was not found in my C# .net web application (button click method and also in Page_Load).An error showing like

'The name 'MessageBox' does not exist in the current context'

Do I need to add any assembly reference for this? (I am using .net framework 4). Is there any alternative method for this?

回答1:

Use This:

System.Web.UI.ScriptManager.RegisterStartupScript(this, typeof(Page), "alert", "alert('" + Message + "')", true);

Hope This help.

回答2:

The key words in your description are

web application

This functionality is only available in client (WinForms, WPF) based applications, not ASP.NET. To do this in a web app you will need to use Javascript, as illustrated in this previous Stack Overflow question.

回答3:

The MessageBox class in the System.Windows.Forms namespace is usable from Windows Forms and Not ASP.NET Web Forms.

回答4:

System.Windows.MessageBox is used in WPF applications and System.Windows.Forms.MessageBox is used in Windows Form applications but your project is WebApplication so you don't have access to any of them.