Impersonation generates "Invalid Cast" error

[Peter Afonin]

Hello:

When I try to access a SQL server or a network share from an ASP.Net
application that I run on my computer, I run into security problems (for
instance, I cannot execute DTS package using Trusted connection or get a
file information using FileInfo class). This is probably because my
application is running under PETER\ASPNET account, where PETER is my
computer's name. I can solve this problem by using Impersonation.

However, when I specify Impersonation in Web.config, it usually creates some
problems when I move my application to the server. So I prefer to
impersonate my application programmaticall y and then cancel it:

Dim impersonationCo ntext As
System.Security .Principal.Wind owsImpersonatio nContext
Dim currentWindowsI dentity As System.Security .Principal.Wind owsIdentity
currentWindowsI dentity = CType(User.Iden tity,
System.Security .Principal.Wind owsIdentity)
impersonationCo ntext = currentWindowsI dentity.Imperso nate()
............... ............... ............... ............... ............... ..
............... .......

impersonationCo ntext.Undo()

Ususally this works OK, but this time the line

currentWindowsI dentity = CType(User.Iden tity,
System.Security .Principal.Wind owsIdentity)

is producing an "Invalid Cast" error. I've noticed that User.Identity is
actually an empty string.

What could be wrong? Is there another way to solve these security issues
besides using Impersonation? I cannot add PETER\ASPNET account to the SQL
server or to the network share permissions.

I would greatly appreciate your suggestions.

Thank you,

--
Peter Afonin