Dim currentUser As System.Security.Principal.WindowsIdentity = _
  System.Security.Principal.WindowsIdentity.GetCurrent()

    Public Function CanWriteTo(ByVal DirectoryPath As String) As Boolean
        Dim dirInfo As System.IO.DirectoryInfo = _
          FileIO.FileSystem.GetDirectoryInfo(DirectoryPath)
        Dim currentUser As System.Security.Principal.WindowsIdentity = _
        System.Security.Principal.WindowsIdentity.GetCurrent()
        Dim currentPrinciple As System.Security.Principal.WindowsPrincipal = _
        System.Threading.Thread.CurrentPrincipal
        Dim acl As System.Security.AccessControl.AuthorizationRuleCollection = _
        dirInfo.GetAccessControl().GetAccessRules(True, True, GetType( _
        System.Security.Principal.SecurityIdentifier))
        Dim currentRule As System.Security.AccessControl.FileSystemAccessRule
        Dim denyread As Boolean = False
        Dim allowread As Boolean = False
 
        For x As Integer = 0 To acl.Count - 1
            currentRule = acl(x)
            If currentUser.User.Equals(currentRule.IdentityReference) Or _
              currentPrinciple.IsInRole(currentRule.IdentityReference) Then
                If currentRule.AccessControlType.Equals( _
                Security.AccessControl.AccessControlType.Deny) Then
                    If (currentRule.FileSystemRights And _
                    Security.AccessControl.FileSystemRights.Write) = _
                    Security.AccessControl.FileSystemRights.Write Then denyread _
                    = True
                Else
                    If currentRule.AccessControlType.Equals( _
                      AccessControlType.Allow) Then allowread = True
                End If
            End If
        Next
 
        If allowread And Not (denyread) Then
            Return True
        Else
            Return False
        End If
 
    End Function

-= Mark Ruhnau =-