Private Sub CommandButton1_Click()
Dim numLigneVide As Integer
Worksheets("DONNEES").Activate
numLigneVide = ActiveSheet.Columns(1).Find("").Row
If TextBox1.Text = "" Then
MsgBox "Please enter your order number", vbCritical, "champs manquant"
Else
If Application.CountIf(Sheets("DONNEES").[A:A], CDbl(TextBox1)) > 0 Then
MsgBox "existe déja !!": Exit Sub
End If
ActiveSheet.Cells(numLigneVide, 1) = TextBox1.Text
TextBox1.Text = ""
End If