折旧计算器修改

Question

正如标题所示，我需要帮助改变旧项目的代码，我正在计划为即将到来的项目进行改造。我需要将Financial.DDB更改为Financial.SLN，而不会因为参数太多而发生错误。另外我认为Main_Form_Load内容应该用lstUsefulLife.Items.Add（“2”）替换为（“20”）。有人可以帮忙吗？这是代码。

Public Class Main_Form

Private Sub Main_Form_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Dim i As Integer
    i = 3
    Do
        lstUsefulLife.Items.Add(i.ToString())
        i = i + 1
    Loop While i <= 20

End Sub

Private Sub btnSchedule_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSchedule.Click
    Dim i As Integer
    Dim amount As Double
    txtSchedule.Text = ""
    txtSchedule.Text = "Year" & vbTab & "Depreciation" & vbNewLine
    Dim years As Integer
    years = Convert.ToDouble(lstUsefulLife.SelectedItem)

    i = 1
    Do
        amount = Financial.DDB(Convert.ToDouble(txtAsset.Text), Convert.ToDouble(txtSalvage.Text), years, i)
        txtSchedule.Text = txtSchedule.Text & i & vbTab & amount.ToString("N2") & vbNewLine
        i = i + 1
    Loop While i <= years
End Sub

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

结束班