Member Avatar for tcon

hi im sorry if this isnt in the right forum but i cant seem to find any threads in this.

i cant seem to create a datetime object in vb.net with datetime string that's in this format "hh:mm:ss tt MM/dd/yy".

The error im getting says its not a recognisable string datetime format.


Any ideas on this?

  • 5 Contributors
  • 15 Replies
  • 2K Views
  • 4 Days Discussion Span
  • Latest Post Latest Post by Luc001

Dani AI

Generated

The string layout you have, time first then date (for example: 12:52:17 PM 11/16/10), is not one of the formats the general parser recognizes. That is why saw TryParse return False. Culture also matters, as pointed out: 11/16/10 only makes sense in an en-US culture. The most robust fix is to use DateTime.TryParseExact with the exact pattern and an explicit culture.

Imports System.Globalization

Dim s = "12:52:17 PM 11/16/10"
Dim formats = {
    "hh:mm:ss tt MM/dd/yy",   ' exact format from the source
    "h:mm:ss tt M/d/yy",      ' tolerate single-digit month/day
    "hh:mm:ss tt MM/dd/yyyy"  ' optionally accept 4-digit year
}
Dim dt As DateTime

If DateTime.TryParseExact(s, formats, CultureInfo.GetCultureInfo("en-US"),
                          DateTimeStyles.None, dt) Then
    ' Use dt as a DateTime. Only format when displaying:
    Dim display = dt.ToString("HH:mm:ss dd/MM/yyyy", CultureInfo.InvariantCulture)
Else
    ' Handle invalid input
End If

A few gotchas to avoid:

  • Use hh with tt for 12-hour input; HH is 24-hour and will not parse with AM/PM.
  • Do not round-trip by formatting to a string and then calling Convert.ToDateTime on that string again. Parse once into a DateTime, store that, and only call ToString for display.
  • With a 2-digit year (yy), .NET maps 00-29 to 2000-2029 and 30-99 to 1930-1999. If that pivot could bite you, require yyyy in the input or include both patterns as shown above.

This keeps the source culture fixed (en-US for MM/dd/yy) while letting you output in any display culture you prefer.

Recommended Answers

All 15 Replies

Member Avatar for codeorder 
Dim myCoolTimeDate As String = Format(DateTime.Now, "hh:mm:ss tt MM/dd/yy")
        MsgBox(myCoolTimeDate)
Edited by codeorder because: n/a
Member Avatar for Luc001

Hi,

If I understand correct then it's this you want to accomplish:

TextBox1.Text = Now.ToString("hh:mm:ss: tt")

TextBox1.Text = Now.ToString("M/dd/yyyy")
Member Avatar for Netcode

for time:

textbox1.text = TimeOfDay.ToShortTimeString

for date:

Today.ToShortDateString()
Member Avatar for tcon

I have a string with a value such as "12:52:17 PM 11/16/10"

I want to create a datetime instance with that string value but vb doen't seem to recognise datetime strings in that format.


To sum up: I need to take a string in "hh:mm:ss tt MM/dd/yy" format and create a datetime object with that string....

Member Avatar for jbrock31 
Dim dtTest As New Date()
        Dim test As String = "12:52:17 PM 11/16/10"
        Dim result As Boolean
        result = Date.TryParse(test, dtTest)
        Me.Label1.Text = dtTest.ToString

This will convert it with the Date first, then the time. Is that ok or do you need the time first?

Member Avatar for tcon

hi jbrock31,

thanks for having a go but 'result' has a false value at debug plus the 'dtTest' date object doesnt take 'test' as its value.

so basically Date.TryParse(test, dtTest) didn't work.

I was wondering could it be a globalisation setting issue? is there a country or globalisation setting in visual studio 2008 that recognises datetime format "hh:mm:ss tt MM/dd/yy"

??


ps thanks to everyone else for trying to help, much appreciated. If ye have any rough ideas as to why it doesn't parse that string into a valid datetime then feel free to share them!

Member Avatar for Netcode

simply use:

Textbox1.text = Now.Date
Member Avatar for Luc001

Hi,

I think that your sytem time isn't the US time format.
To change the forùmat into US time format use this:

Imports System.Globalization 

        Label1.Text = Date.Now.ToString("hh:mm:ss tt MM/d/yyyy", CultureInfo.CreateSpecificCulture("en-US"))

Hope it helps.

Edited by Luc001 because: n/a
Member Avatar for tcon

hey luc001,

have you ever seen a datetime in "hh:mm:ss tt MM/dd/yy" format before?

i need to create a datetime object from a string that has a date string value that is in "hh:mm:ss tt MM/dd/yy" format.

I don't need to get the date and time of system.date.now

Member Avatar for Luc001

Hi,

No it's always first the date and then the time.

After some testing found this:

Dim date1 As Date = #3/7/2008 7:00:00 AM#
        Label1.Text = date1.ToString()
        Dim date2 As Date = #3/7/2008 7:00:00 AM#
        Label2.Text = date1.ToString(System.Globalization.CultureInfo.CreateSpecificCulture("en-US"))
Edited by Luc001 because: n/a
commented: a combination of your posts lead me to a solution when i pieced bits of code together. i will post the final solution soon :) +1
Member Avatar for Luc001

Hi,

You can find some more Time format structures, here.

Edited by Luc001 because: n/a
Member Avatar for tcon

ok i finally got it doing what i want.

it was a culture issue indeed, thanks for that Luc001.

here is my code:

Imports System.Globalization.CultureTypes

Private Function tidyDate(ByVal datetimeval As String) As String
        
        Dim dt As New DateTime()
               dt = DateTime.Parse(datetimeval, System.Globalization.CultureInfo.CreateSpecificCulture("en-US"))
        
Return dt.ToString("HH:mm:ss dd/MM/yyyy")

    End Function

Private Sub form1_Load()

Dim tmpdate As New DateTime()
tmpdate = Convert.ToDateTime(tidyDate("12:57:17 PM 11/16/10"))
messagebox.show(tmpdate.tostring())

End Sub
Member Avatar for Luc001

Hi,

No problem.

If that solution solved your problem then mark your thread as resolved.

Edited by Luc001 because: n/a
Member Avatar for tcon

sorry i thought i marked it when i gave you a plus grade..

ah i see d link now. nice one.

Member Avatar for Luc001

Just to let the others know that your problem is solved.

Thanks for the reputation points :)

Edited by Luc001 because: n/a
Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.