This class exposes a single shared CreateApplicationHost( ) method, which allows you to create an application domain that will be used to process ASP.NET requests. This method accepts three parameters: the hostType (your request-handling class, which will be created in the new domain), virtualDir (the virtual directory for the application domain, such as "/MyApp"), and physicalDir (the physical directory for the application domain where the ASP.NET pages are located, such as "c:\MyApp"). The CreateApplicationHost( ) method returns the live instance of the hostType class.

public sealed class ApplicationHost {
// Public Static Methods
   public static object CreateApplicationHost(Type hostType, string virtualDir, string physicalDir);
}