how to set the Principal policy to WindwosPrincipal ?

[loyal]

hi all I am practising on MCAD training kit book

and heres an example I tried but gave me an exception

specified cast is not valid

and heres the code as an example in my book

 This example assumes that the Principal policy has been set to 
 WindowsPrincipal.
Dim myPrincipal As WindowsPrincipal
 Gets a reference to the current WindowsPrincipal
myPrincipal = CType(Threading.Thread.CurrentPrincipal, _
   WindowsPrincipal)
Dim myIdentity As WindowsIdentity
 Gets the WindowsIdentity of the current principal
myIdentity = CType(myPrincipal.Identity, WindowsIdentity)
 Displays the username of the current user
MessageBox.Show(myIdentity.Name)

 

[PlausiblyDamp]

There is no valid cast from a GenericPrinciple (which Threading.Thread.CurrentPrincipal is) and a WindowsPrinciple.

They both implement the same interface (IPrinciple) so either could be casted to IPrinciple, neither could be casted to the other.

The following should work

 This example assumes that the Principal policy has been set to 
 WindowsPrincipal.
Dim myPrincipal As IPrincipal
 Gets a reference to the current WindowsPrincipal
myPrincipal = DirectCast(Threading.Thread.CurrentPrincipal, _
   IPrincipal)
Dim myIdentity As IIdentity
 Gets the WindowsIdentity of the current principal
myIdentity = DirectCast(myPrincipal.Identity, IIdentity)
 Displays the username of the current user
MessageBox.Show(myIdentity.Name)

 

[loyal]

yeah thanks

but I found this script later in my book to set the

Principal Policy To WindowsPrincipal

AppDomain.CurrentDomain.SetPrincipalPolicy(Security.Principal.PrincipalPolicy.WindowsPrincipal)

 

[Derek Stone]

CurrentPrincipal is defined as IPrincipal, not GenericPrincipal as stated above. It can easily accept any class that implements IPrincipal.