Visual Basic 1002005 [A Developers Notebook] [Electronic resources] نسخه متنی

6.5. Test Group Membership of the Current User

The .NET Framework has always
provided security classes that let you retrieve basic information
about the account of the current user. The new
My.User object provided by Visual Basic 2005 makes
it easier than ever to access this information.

Note: Find out who's using your application, and
the groups a mystery user belongs to.

6.5.1. How do I do that?

Applications often need to test who is running the application. For
example, you might want to restrict some features to certain groups,
such as Windows administrators. You can accomplish this with the
My.User object.

The My.User object provides two key properties
that return information about the current user. These are:

IsAuthenticated

Returns true if the
current user account information is available in the
My.User object. The only reason this information
wouldn't be present is if you've
created a web application that allows anonymous access, or if the
current Windows account isn't associated with the
application domain.

Username

Returns the current username. Assuming
you're using a Windows security policy, this is the
Windows account name for the user, in the form
ComputerName\UserName or
DomainName\UserName.

The My.User object also provides a single method,

IsInRole( ). This method
accepts the name of a group (as a string) and then returns
true if the user belongs to that group. For
example, you could use this technique to verify that the current user
is a Windows administrator before performing a certain task.

To try this out, use the following console application in Example 6-5, which displays some basic information about
the current user and tests if the user is an Administrator.

Note: To check the user and group list for the current computer
(or make changes), select Computer management from the Administrative
Tools section of the Control Panel. Then, expand the System Tools
Local Users and Groups
node.

Example 6-5. Testing the current user identity

Module SecurityTest
Sub Main( )
' Use Windows security. As a result, the User object will
' provide the information for the currently logged in user
' who is running the application.
My.User.InitializeWithWindowsUser( )
Console.WriteLine("Authenticated: " & My.User.Identity.IsAuthenticated)
Console.WriteLine("User: " & My.User.Identity.Username)
Console.WriteLine("Administrator: " & My.User.IsInRole("Administrators"))
End Sub
End Module

Here's the sort of output you'll
see when you run this test:

Authenticated: True
User: FARIAMAT\Matthew
Administrator: True