Member Avatar for raheleh

I use messagebox on a web page but when I upload my file on a virtual directory on a server the messagebox does not work and there are some errors, why?

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Short diagnosis and fix (builds on and ): if your code uses a Windows Forms-style MessageBox on the server it will not appear in the visitor's browser. WinForms dialogs (System.Windows.Forms.MessageBox) are desktop UI calls and belong to desktop apps, not web pages. On a hosted site or IIS virtual directory the process does not have an interactive desktop, so those calls either do nothing or cause errors. See the docs for the WinForms MessageBox for context: System.Windows.Forms.MessageBox.Show.

What to do instead: send a client-side dialog (JavaScript) from the server or render a message into the page. The simplest reliable approach in ASP.NET Web Forms is to register a startup script that emits an alert. For example:

ClientScript.RegisterStartupScript(this.GetType(), "msg", "alert('Your message here');", true);

If the page uses UpdatePanel/AJAX, use ScriptManager.RegisterStartupScript instead: ScriptManager.RegisterStartupScript. The server-side API that registers scripts is documented here: ClientScriptManager.RegisterStartupScript. For the client-side function see window.alert.

Quick tips: escape or encode any user text before embedding it in JavaScript (use HttpUtility.JavaScriptStringEncode or equivalent) to avoid breaking the script or creating an XSS risk. If a non-modal, persistent message is preferred, update a Label/Literal on the page instead of a popup. Finally, confirm the visitor's browser permits JavaScript—alerts require client-side scripting to be enabled.

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Member Avatar for tgreer

Please be more specific. There is no such thing as a "messagebox" in HTML. There are "alerts" and "confirms". Which server control are you using?

Member Avatar for derisen

.if you are using script for displaying the alert message box then you must ensure that javascript is enabled in the browser that you are using. please check it out.

Member Avatar for tgreer

JavaScript is always enabled by default.

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