With source code- Visual Basic.net project: System calculate installments and due dates in VB.net

Public Class Form5

    Dim dt As New DataTable

    Private Sub Form5_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        dt.Columns.Add("Installment", GetType(String))

        dt.Columns.Add("Value", GetType(Integer))

        dt.Columns.Add("Due_date", GetType(Date))

        DataGridView1.DataSource = dt

        

    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

        Dim price_v, adv_payment, installment_value, n_intallments, final_installment As Double

        price_v = TextBox1.Text

        adv_payment = TextBox2.Text

        installment_value = TextBox3.Text

        n_intallments = Math.Ceiling((price_v - adv_payment) / installment_value)

        final_installment = (price_v - adv_payment) Mod installment_value

        DataGridView1.DataSource = Nothing

        dt.Clear()

        DataGridView1.DataSource = dt

        DataGridView1.Columns("Due_date").DefaultCellStyle.Format = "MM-dd-yyyy"

        For i As Integer = 1 To n_intallments

            Dim date_payment = DateAdd(DateInterval.Month, i, Now)

            dt.Rows.Add("Installment" & i, TextBox3.Text, date_payment)

        Next

        If final_installment <> 0 Then

            Dim lastrow As Integer = DataGridView1.Rows.Count - 1

            DataGridView1.Rows(lastrow).Cells(1).Value = final_installment

        End If

    End Sub