VB >> pembayaran gaji pegawai

Public Class Form1
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        nik.Items.Add("101rd")
        nik.Items.Add("102rf")
        nik.Items.Add("103tr")

        gp.Items.Add("a")
        gp.Items.Add("b")
        gp.Items.Add("c")

        sp.Items.Add("menikah")
        sp.Items.Add("BELUM menikah")

    End Sub
    Private Sub nik_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles nik.SelectedIndexChanged
        Select Case nik.Text
            Case "101rd"
                np.Text = "Rudi"
            Case "102rf"
                np.Text = "Yudi"
            Case "103tr"
                np.Text = "Ari"

        End Select

    End Sub

    Private Sub gp_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles gp.SelectedIndexChanged
        Select Case gp.Text
            Case "a"
                gpo.Text = 250000
            Case "b"
                gpo.Text = 350000
            Case "c"
                gpo.Text = 450000
        End Select
        pjk.Text = 0.1 * gpo.Text
    End Sub

    Private Sub sp_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles sp.SelectedIndexChanged
        Select Case sp.Text
            Case "menikah"
                tk.Text = 0.05 * gpo.Text
            Case " BELUM menikah"
                tk.Text = 0 * gpo.Text
        End Select
        tg.Text = gpo.Text - pjk.Text + tk.Text

    End Sub

    Private Sub btnhapus_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnhapus.Click
        nik.Text = ""
        np.Text = ""
        gp.Text = ""
        gpo.Text = ""
        pjk.Text = ""
        tk.Text = ""
        sp.Text = ""
        tg.Text = ""

    End Sub

    Private Sub btnkeluar_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnkeluar.Click
        End

    End Sub
End Class