CODEWITHSUNDEEP
vb.net
w0051977
w0051977

Reputation: 15797

Date type: string literal and date literal - different formatting of date

Please see the code below:

 Private Sub Form1_Load(sender As Object, e As EventArgs) Handles
 Me.Load
         Dim str As String = "1-2-2014"
         Dim dte As Date = CDate(str)
         MsgBox(dte.Month)
     End Sub

The date literal is: #1/2/2014#. This is always interpreted as 2nd January 2014 as discussed here: http://msdn.microsoft.com/en-us/library/3eaydw6e.aspx. However, in the code fragment above the date is interpreted as 1st February 2014. Is the local regional settings used when you pass a string?

Upvotes: 0

Views: 2205

Answers (1)

Ňɏssa Pøngjǣrdenlarp
Ňɏssa Pøngjǣrdenlarp

Reputation: 38875

You are looking at the Date Type MSDN docs, but creating a string "1-2-2014" which is not a Date type and wont act like one. The note about the order and using # applies only to a DateTime variable:

Dim myDt As Date =  #1/2/2014#

Also look at what MSDN says about CDate:

In general, hard-coding dates and times as strings (as shown in this example) is not recommended. Use date literals and time literals, such as #Feb 12, 1969# and #4:45:23 PM#, instead.

As a string, it is difficult to know what format/culture it follows to know how to convert it back. Instead, keep Date-based data items as Date type variables and simple format them for the user, reports, MsgBox etc:

' DISPLAY a date anyway we want, without changing the value:
Console.WriteLine(dt.ToString("hh:mm M/d/yyyy"))    ' => 05:55 2/11/2010
Console.WriteLine(dt.ToString("HH.mm M/d/yyyy"))    ' => 17.55 2/11/2010
Console.WriteLine(dt.ToString("MM/dd/yyyy HH:mm"))  ' => 02/11/2010 17:55

NET and VB are always going to assume a string is in the current culture format, unless told otherwise. CDate is simplified so you cant pass a format, but other convert functions allow you to specify the culture or format:

Dim myStr As String = "17:55 2/11/2010"    ' ad odd date/time format
Dim dtVar As DateTime = DateTime.ParseExact(myDate, 
                           "HH:mm M/dd/yyyy", 
                           Globalization.CultureInfo.InvariantCulture)

Upvotes: 1

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