Application directives specify optional application-specific settings used by the ASP.NET parser when processing ASP.NET global application (.asax) files. Application directives are located at the top of the Global.asax file.
Each directive can contain one or more attribute/value pairs specific to that directive. The following table shows the application directives supported in ASP.NET. Note that the @ Application directive can be used only in Global.asax files, while the other directives are used in other ASP.NET files such as Web pages (.aspx files) and user controls (.ascx files).