Option Explicit
Public Sub test()
Dim avntArray() As Variant
Dim astrTemp() As String
Dim ialngIndex As Long, ialngRow As Long
Dim lngDecr As Long, lngBound As Long
avntArray = Cells(1, 1).Resize(Cells(Rows.Count, 1).End(xlUp).Row, 1).Value
ReDim astrTemp(0) As String
For ialngRow = 1 To UBound(avntArray, 1)
lngBound = UBound(astrTemp)
For ialngIndex = 0 To lngBound
If avntArray(ialngRow, 1) = _
astrTemp(ialngIndex) Then Exit For
Next
If ialngIndex = lngBound + 1 Then
lngDecr = IIf(astrTemp(0) = vbNullString, 1, 0)
ReDim Preserve astrTemp(ialngIndex - lngDecr) As String
astrTemp(ialngIndex - lngDecr) = avntArray(ialngRow, 1)
End If
Next
UserForm1.ComboBox1.List() = astrTemp()
End Sub