Bonjour,
Essaie ainsi (exemple à adapter) :
Option Explicit
Dim n As Double
Private Sub UserForm_Initialize()
Dim i As Byte
Me.TextBox3 = CInt(Year(Date))
n = WorksheetFunction.IsoWeekNum(DateSerial(TextBox3, 12, 28))
For i = 1 To n
Me.ComboBox1.AddItem Format(i, "00")
Next i
Me.ComboBox1 = WorksheetFunction.IsoWeekNum(TextBox3)
End Sub
Private Sub CommandButton1_Click()
Dim ws As Worksheet, rng As Range, i As Long
With Worksheets("BD")
Set rng = .Cells(1).CurrentRegion.Columns(1)
For i = 2 To rng.Rows.Count
If WorksheetFunction.IsoWeekNum(.Cells(i, 1).Value) = Me.ComboBox1 Then
MsgBox .Cells(i, 2).Value
Exit For
End If
Next i
End With
End Sub