如何查找两个日期/ DateTimePickers之间的天数

Question

在我的下面的代码中,如何设置到达日期和降级,以便我可以获得应付金额？我需要设置它们,因为我住在酒店的日子,所以我可以拿出一个总数.如果这有道理吗？我在Visual Basic中使用datetimepickers.

Public Class RentalForm
    'declare constants
    Const tax_rate_decimal As Decimal = 12.25D
    Const king_price_decimal As Decimal = 110.9D
    Const queen_price_decimal As Decimal = 105.9D
    Const double_price_decimal As Decimal = 95.9D

    'declare variables
    Private roomchargesumdecimal, taxamountsumdecimal, amountduesumdecimal As Decimal

    Private Sub exitButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles exitButton.Click
        Close()
    End Sub

    Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBoxnameofguest.TextChanged

    End Sub

    Private Sub calculateButton_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles calculateButton.Click
        'dimension local variables
        Dim numberofguestsinteger As Integer
        Dim roomchargedecimal, taxamountdecimal, amountduedecimal, taxratedecimal As Integer
        Dim arrivaldate, departuredate As Date

        Try
            'dates
            arrivaldate = Now

            'convert quantity to numeric
            numberofguestsinteger = Integer.Parse(TextBoxNumberofguests.Text)

            'calculate values for single person
            roomchargedecimal = numberofguestsinteger * (arrivaldate + departuredate)
            taxratedecimal = roomchargedecimal * tax_rate_decimal   

        Catch ex As Exception

        End Try

    End Sub

    Private Sub DateTimePickerarrivaldate_ValueChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles DateTimePickerarrivaldate.ValueChanged

    End Sub

    Private Sub Label16averagelengthofstay_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Label16averagelengthofstay.Click


    End Sub

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

    End Sub
End Class              

Answer 1

DateTime数学起初可能会令人困惑.但是它们是DateTimePicker控件还是变量并不重要,因为它myDateTimePicker.Value 是一个DateTimeType.因此,您可以混合和匹配变量和控件,例如Arrival as Now和Departure from picker,并使用减法:

Dim arrivaldate As DateTime = DateTime.Now
Dim departuredate As DateTime = Me.DeparturePicker.Value

Dim DaysStayed as Int32 = departuredate.Subtract(arrivaldate).Days

要记住的是结果是TimeSpan对象.如果你看一下结构,你会看到它以单位Days为单位提供了经过的时间Ticks.

上面的代码Days从中TimeSpan创建了一个不创建临时变量的值TimeSpan.其他方式:

Dim tsHotelStay = detarturedate.Value - arrivalDate
wholeDays = tsHotelStay.Days              ' e.g 7
totalDays = tsHotelStay.TotalDays         . e.g. 7.53
totalHrs = tsHotelStay.TotalHours         . eg 180.397

这次,代码确实创建了一个TimeSpan变量(tsHotelDay).请注意,所有属性都以整体和小数形式提供(Ticks除外).

最后,显示(DateTime.Subtract(dt)和myTs = dtA - dtB)的2个减法方法在功能上是相同的:都返回TimeSpan对象.

Answer 2

DateTimePicker 对象有一个Value 属性，它将为每个对象提供一个 DateTime。您可以通过将一个 DateTime 对象与另一个 DateTime 对象相减来获得差异。

PS 不要那样吃掉所有异常。这很不酷。