kegunanaan case pada vb

silakan desain gambarnya dibawah

maka listing programnya sperti dibawah :
Public Class Form1

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Kodebarang.Items.Add("TS001")
        Kodebarang.Items.Add("TS002")
        Kodebarang.Items.Add("VG001")
        Kodebarang.Items.Add("VG002")
    End Sub

    Private Sub Kodebarang_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Kodebarang.SelectedIndexChanged
        Dim X, x2 As String
        X = Microsoft.VisualBasic.Right(Kodebarang.Text, 3)
        Select Case X
            Case "001" : NamaBarang.Text = "FLASDHDISK 4GB"
            Case "002" : NamaBarang.Text = "FLASDHDISK 2GB"
            Case "001" : NamaBarang.Text = "FLASDHDISK 4GB"
            Case "002" : NamaBarang.Text = "FLASDHDISK 2GB"
        End Select
        X = Microsoft.VisualBasic.Left(Kodebarang.Text, 2)
        Select Case X
            Case "TS" : Merk.Text = "THOSIBA"
            Case "VG" : Merk.Text = "V_GEN"
            Case "TS" : Merk.Text = "THOSIBA"
            Case "VG" : Merk.Text = "V_GEN"
        End Select
        x2 = Microsoft.VisualBasic.Right(Kodebarang.Text, 3)
        If X = "TS" And x2 = "001" Then
            harga.Text = 10500
        ElseIf X = "TS" And x2 = "002" Then
            harga.Text = 75000
        ElseIf X = "VG" And x2 = "001" Then
            harga.Text = 90000
        ElseIf X = "VG" And x2 = "002" Then
            harga.Text = 60000
        End If

    End Sub


    Private Sub JmlhBeli_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles JmlhBeli.KeyPress
        Dim tombol As Integer = Asc(e.KeyChar)

        If tombol = 13 Then
            TtlHarga.Text = JmlhBeli.Text * harga.Text

        End If

    End Sub
End Class