Stuff

Public Class Form1
   
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If chiffre1.Text = "" Or op.Text = "" Or chiffre2.Text = "" Then
            MsgBox("Un champ obligatoire doit etre renseigné")
            Exit Sub
        Else
            If (chiffre1.Text = "0" Or chiffre2.Text = "0") And (op.Text = "/" Or op.Text = "*") Then
                MsgBox("Le 0 est interdit dans ce type d'opération")
                Exit Sub
                'ElseIf (chiffre1.Text = "0" Or chiffre2.Text = "0") And op.Text = "*" Then
                '   MsgBox("multiplication par 0 interdite")
                '  Exit Sub
            Else

                Select Case op.Text
                    Case "+" 'Print a short report
                        resultat.Text = (CInt(chiffre1.Text) + CInt(chiffre2.Text)).ToString
                    Case "-" 'Print a long, detailed report
                        resultat.Text = (CInt(chiffre1.Text) - CInt(chiffre2.Text)).ToString
                    Case "/" 'Graph the output
                        resultat.Text = (CInt(chiffre1.Text) / CInt(chiffre2.Text)).ToString
                    Case "*" 'Graph the output
                        resultat.Text = (CInt(chiffre1.Text) * CInt(chiffre2.Text)).ToString
                    Case Else  'All other cases or values of iswitch are an error
                        MsgBox("On me la fait pas hein...")
                End Select
            End If
            'resultat.Text = (CInt(chiffre1.Text) CInt(op.Text) CInt(chiffre2.Text)).ToString 
        End If
    End Sub