If (TextBox1 <> "" And TextBox2 <> "" And TextBox3 <> "" And TextBox4 <> "") _
Or (Val(Replace(TextBox1, ",", ".")) + Val(Replace(TextBox2, ",", ".")) + _
Val(Replace(TextBox3, ",", ".")) + Val(Replace(TextBox4, ",", ".")) <> 100) Then
MsgBox "Attention, la pondération n'est pas correcte."
Exit Sub
End If