vb.net 检查日期是否介于或等于其他两个日期
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Check if date is between or equal to two other dates
提问by alwaysVBNET
I'm trying to check if a date is between two other dates. The two other dates are coming from two DatePickers formatted as dd/mm/yyyy. My code below works but if my searching date is i.e. equal to the from date I get a "Not between" message. If I search for date 17/05/2013 and I set the ranges to bet from: 17/05/2013 and to: 17/05/2013 I want to get a "Between" message. Any ideas?
我试图检查一个日期是否在其他两个日期之间。另外两个日期来自两个格式为 dd/mm/yyyy 的 DatePicker。我下面的代码有效，但如果我的搜索日期等于起始日期，我会收到“不在之间”消息。如果我搜索日期 17/05/2013 并将投注范围设置为：17/05/2013 至：17/05/2013，我想收到“之间”消息。有任何想法吗？
Dim str As String = "srt_inlbp_20130517"
Dim sString As String
sString = str.Substring(str.Length - 8)
Dim dTableDate As Date = Date.ParseExact(str.Substring(str.Length - 8), "yyyyMMdd", Nothing)
Label9.Text = dTableDate
If ((dTableDate >= dFromDate.Value) And (dTableDate <= dToDate.Value)) Then
MsgBox("between")
Else
MsgBox("not between")
End If
回答by Enigmativity
I have rewritten your code in this testable format:
我以这种可测试的格式重写了您的代码：
Dim str As String = "srt_inlbp_20130517"
Dim dTableDate As Date = _
Date.ParseExact(str.Substring(str.Length - 8), "yyyyMMdd", Nothing)
Dim dFromDate As New DateTime(2013, 5, 17)
Dim dToDate As New DateTime(2013, 6, 17)
If ((dTableDate >= dFromDate) And (dTableDate <= dToDate)) Then
Console.WriteLine("between")
Else
Console.WriteLine("not between")
End If
I get the result "between" so I can only suspect that your dFromDate.Valueand/or dToDate.Valueare not as you expect them to be. Can you check this please?
我得到了“介于”之间的结果，所以我只能怀疑你的dFromDate.Value和/或dToDate.Value不是你期望的那样。你能检查一下吗？
回答by Sam Axe
Try to write your comparators like you are reading a number line (e.g. always use a less-than sign).
尝试像阅读数轴一样编写比较器（例如，始终使用小于号）。
Dim questionableDate As Date = New Date(2013, 05, 17)
Dim fromDate As Date = New Date(2013, 05, 17)
Dim toDate As Date = New Date(2013, 05, 17)
If (fromDate <= questionableDate) AndAlso (questionableDate <= toDate) Then
MsgBox("between")
Else
MsgBox("not between")
End If
You'll see that by using the number line approach you can easily determine what the code is doing. The from date and to date are at the ends with the questionable date sandwiched in the middle.
您将看到，通过使用数轴方法，您可以轻松确定代码在做什么。起始日期和截止日期在末尾，可疑日期夹在中间。
Note
笔记
If the code above does not wield the results you expect once you integrate it, then you will need to set some breakpoints and step through your code to see exactly what values your variables have.
如果上面的代码在集成后没有得到您期望的结果，那么您将需要设置一些断点并逐步执行您的代码以准确查看您的变量具有哪些值。
