' Set the WebPermissionAttribute  ConnectPattern property.
<WebPermission(SecurityAction.Deny, ConnectPattern := "http://www\.contoso\.com/Private/.*")> _
    Public Shared Sub CheckConnectPermission(uriToCheck As String)
     Dim re As New Regex("http://www\.contoso\.com/Public/.*")
     Dim con As New WebPermission(NetworkAccess.Connect, re)
     con.Assert()
     Dim permissionToCheck As New WebPermission()
     permissionToCheck.AddPermission(NetworkAccess.Connect, uriToCheck)
     permissionToCheck.Demand()
  End Sub
  
  
  Public Shared Sub demoDenySite()
     'Pass the security check.
     CheckConnectPermission("http://www.contoso.com/Public/page.htm")
     Console.WriteLine("Public page has passed Connect permission check")
     
     Try
        'Throw a SecurityException.
        CheckConnectPermission("http://www.contoso.com/Private/page.htm")
        Console.WriteLine("This line will not be printed")
     Catch e As SecurityException
        Console.WriteLine(("Expected exception" + e.Message))
     End Try
  End Sub