Using arrays

If I want to have an array of strings that I can add to.  How can I do this without keeping track of every time I add a new string.  

So what I have been doing is this...
  Dim myStrings(1000) As String
  Dim myStringCount As Integer


Then while the program is doing its sorting work
   If Not myStrings.Contains(pair.Primary) Then
                myStrings(myStringCount) = pair.Primary
              myStringCount  = myStringCount + 1
    End If

Then when I display them
I do a for loop using myStringCount to display each item
     For i = 0 To myStringCount - 1
            ListBox1.Items.Add(MyStrings(i))
        Next



I'm sure there is a more efficient way.  How would you guys do this?