vb.net 新年第4個星期二

Question

我編寫了一個支票簿應用程序，它將每月的第 4 個星期二存儲在 SQLite 數據庫中，當用戶寫支票並且今天的日期大於存儲的日期時，數據庫中更新了新的第 4 個星期二日期和 function 到存款 SS 付款已加載。
在測試時，我發現當年份更改時，我寫的第一個 Function 會失敗。
所以我寫了第二個 Function 來處理年的變化。
該代碼似乎正在工作。 我想將測試合並到一個 Function 中，因為代碼看起來不夠優雅。 我將在下面發布小型 TEST 應用程序代碼。 這兩個功能在一個模塊中。

Public Class frmStart
Dim varSearchDate As Date
Dim varFTue As Date

Private Sub frmStart_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    tbBox1.Text = "2021-12-28" ' 2021-11-23 2021-12-28 TEST DATES
End Sub

Private Sub btnADD_Click(sender As Object, e As EventArgs) Handles btnADD.Click
    varSearchDate = CDate(tbBox1.Text)
    tbAns.Text = varSearchDate.ToString("M-d-yyyy")

    Dim dateToday = Date.Today
    Dim mo As String
    mo = varSearchDate.ToString("MM")

    If dateToday > varSearchDate And CInt(mo) <> 12 Then
        varFTue = CDate(FourthTueOfNextMonth(Date.Today).ToString("yyyy-M-d"))
        MsgBox("varFTue Next Mo " & varFTue)
        tbBox2.Text = varFTue.ToString("yyyy-M-d")
        'WriteNewFourthTue()
        'gvTxType = "SS Deposit"
    ElseIf dateToday > varSearchDate And CInt(mo) = 12 Then
        varFTue = CDate(FourthTueOfNewYear(Date.Today).ToString("yyyy-M-d"))
        MsgBox("varFTue New Yr " & varFTue)
        tbBox3.Text = varFTue.ToString("yyyy-M-d")
        'WriteNewFourthTue()
        'gvTxType = "SS Deposit"
    End If
End Sub

結束 Class

兩個 function 和我的 TEST 代碼僅使用一個 FUNCTION 注釋掉

Module FunctionModule

'Function FourthTueOfNextMonth(dt As Date) As Date
'    Dim currDate = New Date(dt.Year, dt.Month, 1)
'    Dim nTuesday As Integer
'    While nTuesday < 4
'        If currDate.DayOfWeek = DayOfWeek.Tuesday Then
'            nTuesday += 1
'        End If
'        currDate = currDate.AddDays(1)
'    End While
'    If dt.Month <> 12 Then
'        Return New Date(dt.Year, dt.Month, currDate.Day - 1)
'    ElseIf dt.Month = 12 Then
'        Return New Date(dt.Year + 1, dt.Month - 11, currDate.Day - 1)
'    End If
'End Function

Function FourthTueOfNextMonth(dt As Date) As Date
    Dim currDate = New Date(dt.Year, dt.Month, 1)
    Dim nTuesday As Integer

    While nTuesday < 4
        If currDate.DayOfWeek = DayOfWeek.Tuesday Then
            nTuesday += 1
        End If
        currDate = currDate.AddDays(1)
    End While

    Return New Date(dt.Year, dt.Month, currDate.Day - 1)

End Function

Function FourthTueOfNewYear(dt As Date) As Date
    Dim currDate = New Date(dt.Year + 1, dt.Month - 11, 1)
    Dim nTuesday As Integer

    While nTuesday < 4
        If currDate.DayOfWeek = DayOfWeek.Tuesday Then
            nTuesday += 1
        End If
        currDate = currDate.AddDays(1)
    End While

    Return New Date(dt.Year + 1, dt.Month - 11, currDate.Day - 1)

End Function

端模塊

我的問題有沒有更好的方法來編寫這段代碼，所以我只有一個 Function？

Answer 1

這是一個 function，它根據傳入的日期查找下個月的第四個星期二：

Function FourthTueOfNextMonth(dt As Date) As Date
    ' Start with the First Day of the Month, from the date passed in.
    ' Add one Month to that to get the first Day of the NEXT month.
    Dim currDate As Date = (New Date(dt.Year, dt.Month, 1)).AddMonths(1)
    ' Find the First Tuesday of the Month
    While currDate.DayOfWeek <> DayOfWeek.Tuesday
        currDate = currDate.AddDays(1)
    End While
    ' Add three more Weeks to jump to Fourth Tuesday
    Return currDate.AddDays(21)
End Function

請注意，function 始終返回下個月的第四個星期二，並且它不會檢查傳入的日期是否小於包含傳入日期的同月第四個星期二。