Iam not good at English ,sorry ,but I need help urgently!Thank you!

In Book < ASP.NET Website Programming: Problem - Design - Solution, C# Edition >

The author give a method to implement the Interface IPrincipal.
Then I try to create a class named 'NetPrincipal' implementing this Interface(IPrincipal).In my program,there are some codes like following: context.User=netPrincipal1 //this can run
                      //netPrincipal1 is a instance of NetPrincipal
           //but when change to another page
NetPrincipal n=(NetPrincipal)Contex.User// this can not run
          // error: invalidcasting!


How to solve this problem.

nightsun

Should be...

IPrincipal n = HttpContext.Current.User;

Response.Write( "Authenticated Identity is: " + ((NetPrincipal)n).Identity.Name );
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.
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Good Luck! ;)
-Newton