如何检查输入框值是否在VB中的数组内

Question

I have used this code to fix my problem, but when I use an InputBox it doesn't work.

Private MenuMakanan() As String = {"Sate Kambing", "Sate Ayam", "Gulai", "Nasi"}

Private Sub btn_Pesan_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_Pesan.Click
    Dim myMenu() As String = {}
    Dim jml As Short = InputBox("Mau Pesan Berapa Makanan ? ")
    If jml > 0 Then
        ReDim myMenu(jml - 1)
        For s = 0 To UBound(myMenu)
            myMenu(s) = InputBox("Mau Pesan Makanan Apa ?")
            If MenuMakanan.Contains(myMenu(s)) Then
                lisb_Pesanan.Items.Add(myMenu(s))
            End If
        Next
        MessageBox.Show("Terima Kasih" & vbCrLf & "Mohon tunggu sejenak", "Pesanan", MessageBoxButtons.OK)
    End If
End Sub

If I enter value on InputBox, it will check that it is within the MenuMakanan() array or not, if yes it will add to lisb_Pesanan.

Answer 1

Do you really need the array you are working with?

Especially the way you are working with it ( in the sense that, in case it's not in the menu list, the text will still be added and the lisbox will contain 1 item less than originally ordered?)? I cannot infer the meaning of the text (inside your code, I could use google tranlate, but).

However, your code was checking already (just case sensitive). Now, if you want it Case Insensitive, then you could just go through it with a simple Where statement like

Private MenuMakanan() As String = {"Sate Kambing", "Sate Ayam", "Gulai", "Nasi"}

Private Sub btn_Pesan_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btn_Pesan.Click
    Dim jml As Short = 0
    Dim requested As String = Microsoft.VisualBasic.InputBox("Mau Pesan Berapa Makanan ? ")

    If Not Short.TryParse(requested, jml) OrElse jml <= 0 Then
        ' throw enter a positive number...
        Return
    End If
    If jml > 0 Then
        Do
            Dim menuText As String = Microsoft.VisualBasic.InputBox("Mau Pesan Makanan Apa ?")
            Dim match As String = MenuMakanan.Where(Function(i) String.Equals(i, menuText, StringComparison.CurrentCultureIgnoreCase)).FirstOrDefault() ' contains either the matching menuItem or the default string (nothing)
            If Not String.IsNullOrWhiteSpace(match) Then
                lisb_Pesanan.Items.Add(match)
                jml -= 1
            Else
                ' incorrect entry, throw a message, let the user re-enter the value
                MessageBox.Show("Warning ...", "Warning ...", MessageBoxButtons.OK, MessageBoxIcon.Error)
            End If
        Loop While jml > 0
        MessageBox.Show("Terima Kasih" & vbCrLf & "Mohon tunggu sejenak", "Pesanan", MessageBoxButtons.OK)
    End If
End Sub