Question

我想减去两次。

Sub notifier(checkouttime As Label)
        Dim checktime As New DateTime(checkouttime.Tag)
        Dim currenttime As New DateTime(DateAndTime.TimeOfDay.ToString("hh:mm:ss"))

        Dim balance As TimeSpan = checktime - currenttime
    End Sub

我的checkouttime.tag上的

的时间值格式为“hh：mm：ss”

我必须以相同的格式获取今天的当前时间并实现它，但当我需要减去它们时，我收到错误。

An unhandled exception of type 'System.InvalidCastException' occurred in Microsoft.VisualBasic.dll

Additional information: Conversion from string "08:00:58" to type 'Long' is not valid.

提前致谢

Answer 1

这将尝试解析您的DateTime字符串。您可能需要将日期与保存到Tag属性的日期保存在一起。

Private Function Notifier(checkouttime As Label) As String
   Dim checktime As DateTime
   If DateTime.TryParse(checkouttime.Tag.ToString, checktime) Then
     Dim currenttime As Date = Date.Now
     Return (currenttime - checktime).ToString()
   End If
   Return "Bad Time String"
End Sub

Answer 2

尝试这种格式......

Dim date1 As Date = #2/14/2014 9:35:04 AM#
Dim date2 As Date = #2/28/2014 12:30:54 PM#
Dim duration As TimeSpan = date1 - date2 

MsgBox(duration.ToString)

Answer 3

没关系，我已经为我的问题找到了另一个类似的解决方案，这就是我如何解决它。

Sub notifier(checkouttime As Label)
        Dim checktime As String = checkouttime.Tag
        Dim splitcheck = Split(checktime, ":")
        Dim currenttime As String = CStr(DateAndTime.TimeOfDay.ToString("hh:mm:ss"))
        Dim splitcurrent = Split(currenttime, ":")

        Dim checkMinutes, currentMinutes As Integer

        checkMinutes = CDbl(splitcheck(0)) * 60 + CDbl(splitcheck(1)) + CDbl(splitcheck(2)) / 60
        currentMinutes = CDbl(splitcurrent(0)) * 60 + CDbl(splitcurrent(1)) + CDbl(splitcurrent(2)) / 60

        'Dim balance As String = checkkresult - currentresult

        MsgBox(checkMinutes & " " & currentMinutes & ". While current time is: " & currenttime)
    End Sub

我将时间转换为分钟以实现我的目标。

感谢您的回答。

在VB.net中减去时间

3 个答案: