VB.NET 如何在列表框中获取总小时数和分钟数

Question

请帮忙！我需要从 ListBox 中获取格式为 "HH:mm" 的总小时数和分钟数，例如：

    11:20
    22:40
    34:00

总计：68:00

我尝试使用 Datetime 和 TimeSpan，但出现错误：

"The DateTime represented by the string is not supported in calendar System.Globalization.GregorianCalendar."

这是我的代码：

    ListBox_monthtime.Items.Add("11:20")
    ListBox_monthtime.Items.Add("22:40")
    ListBox_monthtime.Items.Add("34:00")

    'SUM TIMES IN LISTBOX
    Dim MyDateTimeMonthly As DateTime
    Dim MyTimeSpanMonthly As New TimeSpan

    For Each S As String In ListBox_monthtime.Items
        MyDateTimeMonthly = DateTime.ParseExact(S, "HH:mm", System.Globalization.CultureInfo.InvariantCulture)
        MyTimeSpanMonthly = MyTimeSpanMonthly.Add(New TimeSpan(MyDateTimeMonthly.Day, MyDateTimeMonthly.Hour, MyDateTimeMonthly.Minute, 0))
    Next

    monthtime_txt.Text = (MyTimeSpanMonthly.Days * 24 + MyTimeSpanMonthly.Hours) & ":" & MyTimeSpanMonthly.Minutes

Answer 1

也许这会有所帮助：

ListBox_monthtime.Items.Add("11:43")
ListBox_monthtime.Items.Add("22:56")
ListBox_monthtime.Items.Add("34:21")

Dim totalHours As Integer
Dim totalMinutes As Integer
For Each S As String In ListBox_monthtime.Items
    totalHours += S.Split(":")(0)
    totalMinutes += S.Split(":")(1)
Next

Dim remainder = totalMinutes Mod 60
totalHours += totalMinutes / 60

Dim totalTime = totalHours & ":" & remainder.ToString("D2")
monthtime_txt.Text = totalTime

虽然你仍然会转换字符串-整数，所以我会把它放在 Try/Catch

Answer 2

您不能使用大于 24 的小时值从字符串创建 DateTime 或 Timespan。您需要自己解析输入并将其转换为有效字符串以供 TimeSpan.parse() 使用.

Dim TotalTime As TimeSpan = TimeSpan.Zero
For Each item As String In ListBox_monthtime.Items
    TotalTime = TotalTime.Add(TimeSpan.Parse(FormatTimeString(item)))
Next
Me.monthtime_txt.Text = $"{CInt(TotalTime.TotalHours).ToString}:{TotalTime.Minutes}"


Private Function FormatTimeString(TimeString As String) As String
    Dim timeArr() As String = TimeString.Split(":")
    If CInt(timeArr(0)) > 24I Then
        Dim d As Int32 = CInt(timeArr(0)) \ 24I
        FormatTimeString = $"{d}:{(CInt(timeArr(0)) - (24I * d)).ToString}:{timeArr(1)}:00"
    Else
        FormatTimeString = TimeString
    End If
End Function

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