Coding PV: Asuransi (errorProvider)

Public Class Form1
    Dim st As String
    Dim inz(0, 6) As String
    Dim ii As Integer = 0
    Dim jml As Integer
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        cek()
        simpandata()
        hitung()
        tampilan()
        bersih()

    End Sub
    Private Sub bersih()
        TextBox1.Text = ""
        TextBox2.Text = ""
        TextBox4.Text = ""
        ComboBox1.Text = ""
        RadioButton1.Checked = False
        RadioButton2.Checked = False
    End Sub
    Private Function cek()
        If RadioButton1.Checked = True Then
            st = "Baru"
        ElseIf RadioButton2.Checked = True Then
            st = "Perpanjangan"
        End If
        Return st
    End Function
    Private Sub tampilan()
        ListView1.Items.Add(TextBox1.Text)
        ListView1.Items(ListView1.Items.Count - 1).SubItems.Add(TextBox2.Text)
        ListView1.Items(ListView1.Items.Count - 1).SubItems.Add(ComboBox1.Text)
        ListView1.Items(ListView1.Items.Count - 1).SubItems.Add(TextBox4.Text)
        ListView1.Items(ListView1.Items.Count - 1).SubItems.Add(st)
        ListView1.Items(ListView1.Items.Count - 1).SubItems.Add(jml)

    End Sub
    Private Sub simpandata()
        inz(ii, 0) = TextBox1.Text
        inz(ii, 1) = TextBox2.Text
        inz(ii, 2) = ComboBox1.Text
        inz(ii, 3) = TextBox4.Text
        inz(ii, 4) = st
        inz(ii, 5) = jml
        ii = ii + 1
        ReDim inz(1, 6)
    End Sub
    Private Sub isicombo()
        ComboBox1.Items.Add("Mobil")
        ComboBox1.Items.Add("Sepeda Motor")
    End Sub
    Public Function hitung() As Integer
        If st = "Baru" Then
            jml = (CInt(TextBox4.Text) / 60) + ((CInt(TextBox4.Text) / 60) * 0.15)
        ElseIf st = "Perpanjangan" Then
            jml = (CInt(TextBox4.Text) / 60) + ((CInt(TextBox4.Text) / 60) * 0.1)
        End If
    End Function

    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        isicombo()
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Application.Exit()
    End Sub

    Private Sub TextBox2_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles TextBox2.Validating
        If TextBox2.Text = "" Then
            ErrorProvider1.SetError(TextBox1, "Data Nama masih Kosong")

        End If
    End Sub

    Private Sub ComboBox1_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles ComboBox1.Validating
        If TextBox1.Text = "" Then
            ErrorProvider1.SetError(TextBox1, "Harap Memilih Jenis Asuransi")

        End If
    End Sub

    Private Sub TextBox4_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles TextBox4.Validating
        If TextBox1.Text = "" Then
            ErrorProvider1.SetError(TextBox1, "Harga Masih Kosong")

        End If

    End Sub

    Private Sub Button1_Validating(ByVal sender As Object, ByVal e As System.ComponentModel.CancelEventArgs) Handles Button1.Validating
        If TextBox1.Text = "" Then
            ErrorProvider1.SetError(TextBox1, "Tidak Boleh Kosong")
        Else
            ErrorProvider1.SetError(TextBox1, "")
        End If
        If IsNumeric(TextBox2.Text) = True Then
            ErrorProvider1.SetError(TextBox2, "Harus Huruf")
        Else
            ErrorProvider1.SetError(TextBox2, "")
        End If
        If IsNumeric(TextBox4.Text) = True Then
            ErrorProvider1.SetError(TextBox4, "Harus Angka")
        Else
            ErrorProvider1.SetError(TextBox4, "")
        End If
        If RadioButton1.Checked = False And RadioButton2.Checked = False Then
            ErrorProvider1.SetError(RadioButton1, "Harus pilih salah satu")
        Else
            ErrorProvider1.SetError(RadioButton1, "")
        End If
    End Sub
End Class