How to call an ASP.NET WebMethod in a UserControl (.ascx)

WebMethod should be static. So, You can put it in the user control and add a method in the page to call it.

Edit:

You can not call a web method through a user control because it’ll be automatically rendered inside the page.

The web method which you have in the user control:

public static string HelloWorld()
{
    return "helloWOrld";
}

In the Page class add the web method:

[WebMethod]
public static string HelloWorld()
{
    return ArticleList.HelloWorld(); // call the method which 
                                     // exists in the user control
}