Here is the original excel code I would like to change to work in outlook. 
Private Sub UserForm_Activate()
'''start of what I added for my listbox
   Dim fn As String, ff As Integer, txt As String
    fn = "C:\test\project_list.txt" '< --- .txt file path contains folders on server
    txt = Space(FileLen(fn))
    ff = FreeFile
    Open fn For Binary As #ff
    Get #ff, , txt
    Close #ff
 
 Dim myArray() As String
  'Use Split function to return a zero based one dimensional array.
  myArray = Split(txt, vbCrLf)
  'Use .List method to populate listbox.
  lstDetail.List = myArray
lbl_Exit:
  Exit Sub
'''' end of what I added
'Set loActive = ActiveSheet.ListObjects(1)
Me.lstDetail.TextColumn = 2
Me.lstDetail.MatchEntry = fmMatchEntryComplete
ResetFilter
End Sub
Function ValidLikePattern(LikePattern As String) As Boolean
Dim temp As Boolean
On Error Resume Next
temp = ("A" Like "*" & LikePattern & "*")
If Err.Number = 0 Then
    ValidLikePattern = True
End If
On Error GoTo 0
End Function
Sub ResetFilter()
'Dim rngTableCol As Excel.Range 'removed from original
Dim varTableCol As Variant
Dim RowCount As Long
Dim collUnique As Collection
Dim FilteredRows() As String
Dim i As Long
Dim ArrCount As Long
Dim FilterPattern As String
Dim UniqueValuesOnly As Boolean
Dim UniqueConstraint As Boolean
Dim CaseSensitive As Boolean
'the asterisks make it match anywhere within the string
If Not ValidLikePattern(Me.txtFilter.Text) Then
    Exit Sub
End If
FilterPattern = "*" & Me.txtFilter.Text & "*"
UniqueValuesOnly = Me.chkUnique.Value
CaseSensitive = Me.chkCaseSensitive
'used only if UniqueValuesOnly is true
Set collUnique = New Collection
Set rngTableCol = loActive.ListColumns(1).DataBodyRange 'this is where things start to go wrong
note that Transpose won't work with > 65536 rows
varTableCol = Application.WorksheetFunction.Transpose(rngTableCol.Value) 
RowCount = UBound(varTableCol)
ReDim FilteredRows(1 To 2, 1 To RowCount)
For i = 1 To RowCount
    If UniqueValuesOnly Then
        On Error Resume Next
        'reset for this loop iteration
        UniqueConstraint = False
        'Add fails if key isn't UniqueValuesOnly
        collUnique.Add Item:="test", Key:=CStr(varTableCol(i))
        If Err.Number <> 0 Then
            UniqueConstraint = True
        End If
        On Error GoTo 0
    End If
    'True if UniqueValuesOnly is false or if
    'UniqueValuesOnly is True and this is the
    'first occurrence of the item
    If Not UniqueConstraint Then
        'Like operator is case sensitive,
        'so need to use LCase if not CaseSensitive
        If (Not CaseSensitive And LCase(varTableCol(i)) Like LCase(FilterPattern)) _
           Or (CaseSensitive And varTableCol(i) Like FilterPattern) Then
            'add to array if ListBox item matches filter
            ArrCount = ArrCount + 1
            'there's a hidden ListBox column that stores the record num
            FilteredRows(1, ArrCount) = i
            FilteredRows(2, ArrCount) = varTableCol(i)
        End If
    End If
Next i
If ArrCount > 0 Then
    'delete empty array items
    'a ListBox cannot contain more than 65536 items
    ReDim Preserve FilteredRows(1 To 2, 1 To Application.WorksheetFunction.Min(ArrCount, 65536))
Else
    're-initialize the array
    Erase FilteredRows
End If
If ArrCount > 1 Then
    Me.lstDetail.List = Application.WorksheetFunction.Transpose(FilteredRows)
Else
    Me.lstDetail.Clear
    'have to add separately if just one match
    'or we get two rows, not two columns, in ListBox
    If ArrCount = 1 Then
        'Me.lstDetail.AddItem FilteredRows(1, 1)
        Me.lstDetail.List(0, 1) = FilteredRows(2, 1)
    End If
End If
End Sub
Private Sub txtFilter_Change()
ResetFilter
End Sub
Private Sub chkCaseSensitive_Click()
ResetFilter
End Sub
Private Sub chkUnique_Click()
ResetFilter
End Sub

''removed from original
'Private Sub lstDetail_Change()
'GoToRow
'End Sub
''removed from original
'Sub GoToRow()
'If Me.lstDetail.ListCount > 0 Then
'    Application.GoTo loActive.ListRows(Me.lstDetail.Value).Range.Cells(1), True
'End If
'End Sub
I ran the debug and rem out invalid items and then tried to fix the code to work with outlook.
Any help would be appreciated.