Convert a string to a datetime - vb.net

I am developing asp.net site using vb framework 3.5.
Im having difficulties converting string data into Date
I tried using cdate function,
I have a variable sdate which is a string variable and date is stored in it which comes from textbox as dd/mm/yyyy now i want to convert this string into a Date variable as i need to perform the operations as Add a day or Subtract a day.
Please guide me how to go about this. i get the error on 3rd line as,String was not recognized as a valid DateTime. I have tried to do as follows but the error comes
Dim sdate As String
Dim expenddt As Date
expenddt = Date.Parse(edate)
expenddt = expenddt.AddDays(-1)
But i get the error as
Conversion from String to type Date is not valid.
How can I get a Date from the string?

You should have to use Date.ParseExact or Date.TryParseExact with correct format string.
Dim edate = "10/12/2009"
Dim expenddt As Date = Date.ParseExact(edate, "dd/MM/yyyy",
System.Globalization.DateTimeFormatInfo.InvariantInfo)
OR
Dim format() = {"dd/MM/yyyy", "d/M/yyyy", "dd-MM-yyyy"}
Dim expenddt As Date = Date.ParseExact(edate, format,
System.Globalization.DateTimeFormatInfo.InvariantInfo,
Globalization.DateTimeStyles.None)
OR
Dim format() = {"dd/MM/yyyy", "d/M/yyyy", "dd-MM-yyyy"}
Dim expenddt As Date
Date.TryParseExact(edate, format,
System.Globalization.DateTimeFormatInfo.InvariantInfo,
Globalization.DateTimeStyles.None, expenddt)

Nobody mentioned this, but in some cases the other method fails to recognize the datetime...
You can try this instead, which will convert the specified string representation of a date and time to an equivalent date and time value
string iDate = "05/05/2005";
DateTime oDate = Convert.ToDateTime(iDate);
MessageBox.Show(oDate.Day + " " + oDate.Month + " " + oDate.Year );

Try to see if the following code helps you:
Dim iDate As String = "05/05/2005"
Dim oDate As DateTime = Convert.ToDateTime(iDate)

Try converting date like this:
Dim expenddt as Date = Date.ParseExact(edate, "dd/mm/yyyy",
System.Globalization.DateTimeFormatInfo.InvariantInfo);
Hope this helps.

Try to use DateTime.ParseExact method, in which you can specify both of datetime mask and original parsed string.
You can read about it here: MSDN: DateTime.ParseExact

Related

Difficulty with formatting a string to parse to date in vb.net

dim dt as string= "03/22/20 20:12:27.320"
Dim tempDate As DateTime = DateTime.ParseExact(dt, "MM/dd/yy hh:mm:ss.fff", CultureInfo.GetCultureInfo("en-US").DateTimeFormat)
This gives error sometimes : System.FormatException: 'String was not recognized as a valid DateTime.'
Why? It seems to be formatted properly. VB.net 4.6.1 framework
"hh" is 12-hour format. 20 is obviously not a valid hour in 12-hour format. If you want 24-hour format then use "HH".
Have you tried to use CDate() function?
dim dt as string= "03/22/20 20:12:27.320"
dim tempDate as Datetime = Cdate(dt)
or
dim tempDate as Datetime = Cdate("03/22/20 20:12:27.320")

VB.net yyyymmdd format needs to parse as date [duplicate]

I am developing asp.net site using vb framework 3.5.
Im having difficulties converting string data into Date
I tried using cdate function,
I have a variable sdate which is a string variable and date is stored in it which comes from textbox as dd/mm/yyyy now i want to convert this string into a Date variable as i need to perform the operations as Add a day or Subtract a day.
Please guide me how to go about this. i get the error on 3rd line as,String was not recognized as a valid DateTime. I have tried to do as follows but the error comes
Dim sdate As String
Dim expenddt As Date
expenddt = Date.Parse(edate)
expenddt = expenddt.AddDays(-1)
But i get the error as
Conversion from String to type Date is not valid.
How can I get a Date from the string?
You should have to use Date.ParseExact or Date.TryParseExact with correct format string.
Dim edate = "10/12/2009"
Dim expenddt As Date = Date.ParseExact(edate, "dd/MM/yyyy",
System.Globalization.DateTimeFormatInfo.InvariantInfo)
OR
Dim format() = {"dd/MM/yyyy", "d/M/yyyy", "dd-MM-yyyy"}
Dim expenddt As Date = Date.ParseExact(edate, format,
System.Globalization.DateTimeFormatInfo.InvariantInfo,
Globalization.DateTimeStyles.None)
OR
Dim format() = {"dd/MM/yyyy", "d/M/yyyy", "dd-MM-yyyy"}
Dim expenddt As Date
Date.TryParseExact(edate, format,
System.Globalization.DateTimeFormatInfo.InvariantInfo,
Globalization.DateTimeStyles.None, expenddt)
Nobody mentioned this, but in some cases the other method fails to recognize the datetime...
You can try this instead, which will convert the specified string representation of a date and time to an equivalent date and time value
string iDate = "05/05/2005";
DateTime oDate = Convert.ToDateTime(iDate);
MessageBox.Show(oDate.Day + " " + oDate.Month + " " + oDate.Year );
Try to see if the following code helps you:
Dim iDate As String = "05/05/2005"
Dim oDate As DateTime = Convert.ToDateTime(iDate)
Try converting date like this:
Dim expenddt as Date = Date.ParseExact(edate, "dd/mm/yyyy",
System.Globalization.DateTimeFormatInfo.InvariantInfo);
Hope this helps.
Try to use DateTime.ParseExact method, in which you can specify both of datetime mask and original parsed string.
You can read about it here: MSDN: DateTime.ParseExact

How CDATE perform its conversion from string to date on VB.NET

I just want to ask how VB.NET perform is conversion of date from string. I am currently designing a database view and convert the date into MMddyyyy format, but I am worried that CDATE it will read it as ddMMyyyy.
I want it to make it shorter and converting the date using CDATE instead of using the traditional M/d/yyyy h:mm:ss tt.
Example:
Dim myDate As Date = CDate(DataTable.Rows(0).Item("DateValue").ToString())
CDate depends on the control panel regional settings and is not recommended - you should use Date.ParseExact instead
Const MyDateFormat As String = "MMddyyyy"
Dim dte As Date = #2/1/2003#
'convert the date to a string
Dim strDate As String = dte.ToString(MyDateFormat)
'convert the string back to a date
Dim dte2 As Date = Date.ParseExact(strDate, MyDateFormat, System.Globalization.CultureInfo.InvariantCulture)
If dte = dte2 Then
MsgBox("They're the same :-) " & strDate)
Else
MsgBox("They're different :-(")
End If
For your code, it would look like:
Dim myDate As Date = Date.ParseExact(DataTable.Rows(0).Item("DateValue").ToString(), "MMddyyyy", System.Globalization.CultureInfo.InvariantCulture)

VB.NET String Data Manipulation for DateTimePicker

I want to manipulate my String data for example I have a x="20140118"
to y="01/18/2014" how can I do it? I need it for the value in DateTimePicker on VB.NET.
Thanks
DateTimePicker.Value wants a DateTime not a string. So you need to parse it:
Dim dt As DateTime = DateTime.ParseExact("20140118", "yyyyMMdd", CultureInfo.InvariantCulture)
dateTimePicker1.Value = dt
DateTime.ParseExact
Custom Date and Time Format Strings
However, just for the sake of completeness, if you need a string 01/18/2014 from the DateTime you can use DateTime.ToString:
Dim date As String = dt.ToString("MM/dd/yyyy", CultureInfo.InvariantCulture)
If that is your local date format you could also use these more concise approaches:
)
Dim date As String = dt.ToShortDateString()
)
Dim date As String = dt.ToString("d")

Date time to string conversion

I have to convert a string to date time...
String data is in this form: 13.6.2013. 8:06:36
The code:
Dim pDate As String
pDate = TextBox16.Text
Dim pro_Date As DateTime = DateTime.ParseExact(pDate, "DD.M.YYYY. hh24:mm:ss", CultureInfo.InvariantCulture)
And the error I get is: string was not recognized as a valid datetime
How to convert this?
The format string is case sensitive, so this does not work: "DD.M.YYYY". Also, 24h clock is uppercase H not "hh24". You need a single H because 8:06:36 has no leading zero on the hour.
Dim pro_Date As DateTime = DateTime.ParseExact(pDate, "dd.M.yyyy. H:mm:ss", CultureInfo.InvariantCulture)
More informations acc. the "H" Custom Format Specifier