[2005] adding objects to collection - slow?

[SammyWaslow]

I'm rewriting my app from a more classic Vb approach to a more OOP approach.

I got a class (in progress):

Public Class MyMovie
    Private strMovie As String
    Private strYear As String
    Private SubExtensions() As String = {".srt", ".sub"}
 
    Public Sub New(ByVal FullMovieName As String)
        strMovie = FullMovieName
    End Sub
 
    Public ReadOnly Property Name() As String
        Get
            Return My.Computer.FileSystem.GetFileInfo(strMovie).Name.ToString
        End Get
    End Property
 
    Public ReadOnly Property Folder() As String
        Get
            Return My.Computer.FileSystem.GetFileInfo(strMovie).Directory.FullName
        End Get
    End Property
 
    Public Property Year() As String
        Get
            Return strYear
        End Get
        Set(ByVal value As String)
            strYear = value
        End Set
    End Property
 
    Public ReadOnly Property Subs() As Boolean
        Get
            Return HasSubs()
        End Get
    End Property
 
    Private Function HasSubs() As Boolean
        Dim strExt As String
        Dim strMovieExt As String = strMovie.Trim.Substring((strMovie.Trim.Length) - 4, 4)
        Dim strSub As String = strMovie.Trim.Substring(0, (strMovie.Trim.Length) - 4) 'strip extension
 
        'is there a file with the same name and a sub extension ?
        For Each strExt In SubExtensions
            If System.IO.File.Exists(strSub & strExt) Then
                Return True
                Exit Function
            End If
        Next
        Return False
    End Function
 
End Class

Basicly I'm looping through a collection of files and depending on the extension Add an instance of my class to a Collection

Private colMovies As New Collection

(...)
                If booIsMovie Then
                    If Not colMovies.Contains(strFile) Then 'Only add unique movies files to collection
                        Dim newMovie As New MyMovie(strFile)
                        colMovies.Add(newMovie, strFile)
                    End If
                End If
(...)

Thing is, the adding to the collection is rather slow. Also when I loop through
the collection (for testing) and show a message box with some info on each movie object, there's a noticably delay between closing a messagebox and the next one showing up.

Is this normal or Am I doing something wrong ?