Tugas 3.2 visual basic

Private Sub Cmdbatal_Click()
Cbokodebuku.SetFocus
Cbokodebuku = ""
Txtjb = ""
Txtpengarang = ""
Txttt = ""
Txtpenerbit = ""
Txtharga = ""
End Sub

Private Sub Cmdkeluar_Click()
End
End Sub

Private Sub Cmdlagi_Click()
Cbokodebuku.SetFocus
Cbokodebuku = ""
Txtjb = ""
Txtpengarang = ""
Txttt = ""
Txtpenerbit = ""
Txtharga = ""
End Sub

Private Sub Cmdproses_Click()
Dim S As String
Txttt = "20" & Right(Cbokodebuku, 2)
S = Left(Cbokodebuku, 1)
If S = "A" Then
Txtpenerbit = "Andi Offset Yogyakarta"
ElseIf S = "I" Then
Txtpenerbit = "Indah Surabaya"
ElseIf S = "S" Then
Txtpenerbit = "Salemba Empat"
ElseIf S = "E" Then
Txtpenerbit = "Elek Media Komputindo"
ElseIf S = "M" Then
Txtpenerbit = "Maxicom"
End If
S = Mid(Cbokodebuku, 3, 3)
If S = "SIM" Then
Txtjb = "Sistem Informasi Managemen"
Txtpengarang = "Yati Nur Oktavia"
Txtharga = "75900"
ElseIf S = "EDP" Then
Txtjb = "Elektronik Data Processing"
Txtpengarang = "Imam Tarmizi"
Txtharga = "62000"
ElseIf S = "MNJ" Then
Txtjb = "Manajemen"
Txtpengarang = "Valentina Mariana Adiwianti"
Txtharga = "42000"
ElseIf S = "CDR" Then
Txtjb = "Corel Draw"
Txtpengarang = "Riyan Suhandi"
Txtharga = "53000"
ElseIf S = "RPL" Then
Txtjb = "Rekayasa Perangkat Lunak"
Txtpengarang = "Sinta Umpu Singa"
Txtharga = "83000"
End If
End Sub

Private Sub Form_Load()
Cbokodebuku.AddItem "A-SIM-01"
Cbokodebuku.AddItem "I-EDP-02"
Cbokodebuku.AddItem "S-MNJ-03"
Cbokodebuku.AddItem "E-CDR-04"
Cbokodebuku.AddItem "M-RPL-05"
End Sub