Pb avec combobox

Private Sub UserForm_Initialize()
Dim col As New Collection
Dim c As Range, sh As Worksheet
Dim Listdata() As String
Dim i As Long
With Worksheets("Feuil1")
On Error Resume Next
For Each c In .Range("a2:a" & .Range("A" & .Rows.Count).End(xlUp).Row)
    col.Add c, CStr(c)
Next c
    ReDim Listdata(col.Count - 1)
For i = 0 To col.Count - 1
    Listdata(i) = col(i + 1)
Next i
Me.ComboBox1.List = Listdata
End With
On Error GoTo 0
End Sub

Private Sub CommandButton2_Click()
Dim c As Range, sh As Worksheet
........................................................
' remplir les listbox ou combobox après enregistrement
if me.ComboBox1.ListIndex=-1 then RempListCombo Me.ComboBox1, "Feuil1", "a"
...........................................................


Private Sub UserForm_Initialize()
RempListCombo Me.ComboBox1, "Feuil1", "a"
RempListCombo Me.ComboBox2, "Feuil1", "b"
End Sub


Private Sub RempListCombo(Controlebox As MSForms.Control, Feuil As String, Cola As String)
Dim Col As New Collection
Dim c As Range, sh As Worksheet
Dim Listdata() As String
Dim i As Long
Dim M As Long
Dim N As Long
Dim Temp As String

With Worksheets(Feuil)
On Error Resume Next
For Each c In .Range(Cola & "2:" & Cola & .Range(Cola & .Rows.Count).End(xlUp).Row)
    Col.Add c, CStr(c)
Next c
    ReDim Listdata(Col.Count - 1)
For i = 0 To Col.Count - 1
    Listdata(i) = Col(i + 1)
Next i

For N = 0 To UBound(Listdata)
 For M = 0 To UBound(Listdata)
    If Listdata(M) > Listdata(N) Then
       Temp = Listdata(N)
       Listdata(N) = Listdata(M)
       Listdata(M) = Temp
    End If
 Next M
Next N
Controlebox.clear
Controlebox.List = Listdata
End With
On Error GoTo 0
End Sub

Private Sub ComboBox1_Change()
Dim coll As New Collection
Dim C As Range, sh As Worksheet
Dim Listdata() As String
Dim i As Long
Dim M As Long
Dim N As Long
Dim Temp As String
Dim FirstAddress As String
If ComboBox1.ListIndex = -1 Then Exit Sub


With Sheets("Feuil1")
On Error Resume Next
    With .Range("a1:a" & .Range("a" & .Rows.Count).End(xlUp).Row)
        Set C = .Find(ComboBox1, LookIn:=xlValues, LookAt:=xlWhole)
        If Not C Is Nothing Then
            FirstAddress = C.Address
            Do
                coll.Add C.Offset(0, 1), CStr(C.Offset(0, 1))
                Set C = .FindNext(C)
            Loop While Not C Is Nothing And C.Address <> FirstAddress
        End If
    End With
End With

ReDim Listdata(coll.Count - 1)
For i = 0 To coll.Count - 1
    If coll(i + 1) <> "" Then Listdata(i) = coll(i + 1)
Next i
For N = 0 To UBound(Listdata)
    For M = 0 To UBound(Listdata)
       If Listdata(M) > Listdata(N) Then
          Temp = Listdata(N)
          Listdata(N) = Listdata(M)
          Listdata(M) = Temp
       End If
    Next M
Next N
With Me.ComboBox2
    .Clear
    .List = Listdata
End With


On Error GoTo 0


End Sub