动态计时器 ListView 将在 VB.NET 后使票过期

Question

我正在制作一个应用程序来跟踪我的工作票，但我对日期有疑问。我正在使用计时器从 date2 中减去 date1，但它不起作用。计时器计数以天为单位。

我想知道的是：为什么一分钟后天数变为0？

 If ComboBox1.Text = "" Then
    Else
        Dim pItem As New ListViewItem
        Timer1.Stop()
        pItem.Text = ComboBox1.Text
        pItem.SubItems.Add(Now.ToString)
        pItem.SubItems.Add(Strings.Format(DateTimePicker1.Value))
        pItem.SubItems.Add(DateDiff(DateInterval.Day, Now, CDate(DateTimePicker1.Text & " " & Now.TimeOfDay.ToString())).ToString & " Dias")
        '& Now.Hour.ToString & "Horas" & Now.Minute.ToString & "Minutes")
        ListView1.Items.Add(pItem)
        ListView1.Refresh()

        Timer1.Start()
    End If

If Me.ListView1.Items.Count > 0 Then
  For Each Item As ListViewItem In ListView1.Items
    Dim TimeItem As String = Item.SubItems(2).Text  
    Dim DIfference As String = DateDiff(DateInterval.Second, Now, CDate(TimeItem)).ToString & " Days"
  Next
End If

    Me.ListView1.Refresh()
    'CheckListView()

Public Sub CheckListView()
    For Each item As ListViewItem In Me.ListView1.Items
        If CDate(item.SubItems(2).Text) < Now Then 'Get the date of the item
            Dim NewIt As New ListViewItem
            NewIt.Text = item.Text
            NewIt.SubItems.Add(item.SubItems(1).Text)
            NewIt.SubItems.Add(item.SubItems(2).Text)
            NewIt.SubItems.Add("To Delete")
            Me.ListView1.Items.Add(NewIt)
            ListView1.Items.RemoveAt(item.Index)
        End If
    Next

    ListView1.Refresh()

Answer 1

我不明白 Timer 与它有什么关系，但这里有一些代码，您可以使用它来获得所需的东西。

Dim StartDate As Date = DateTimePicker1.Value
Dim CurrentDate As Date = Now
Dim mySpan As TimeSpan = CurrentDate.Subtract(StartDate)
Debug.Print($"Raw Span {mySpan}")
Debug.Print("TotalDays" & CInt(mySpan.TotalDays).ToString)
Debug.Print($"Days: {mySpan.Days}")
Debug.Print($"Hours: {mySpan.Hours}")

动态计时器 ListView 将在 VB.NET 后使票过期

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