Convert datetime into another format

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Hi I have the following codes in VB. I have a variable in DateTime and I tried to convert the format of returned value from database into yyyy-MM-dd HH:mm:ss I have tried to convert it into string so that I may alter its format but seems like it does not work as expected. Below is my codes:

VB.NET

Dim woStartDate As DateTime
While readerSQL.Read()
      If Not IsDBNull(readerSQL.Item("WOStartDate")) Then
         woStartDate = readerSQL.Item("WOStartDate") '11/8/2016 1.52 PM
         woStartDate = woStartDate.ToString("yyyy-MM-dd HH:mm:ss") '2016-11-08 13:52:21(expected result)
      Else
         woStartDate = DateTime.Now
      End If
End While

The value stay in the same original format after conversion. I have used this function plenty of times(in other program) and it seems not have any problem converting.

What I have tried:

1. Tried to convert readerSQL.Item("WOStartDate") into string directly but returns error.

Posted 7-Nov-16 18:55pm

Jamie888

Updated 7-Nov-16 22:07pm

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Ralf Meier 8-Nov-16 1:10am

Are you sure that your code-part after the IF is worked ...?
I suppose that you get a IsDBNull from the Item and because of this your code workes in the ELSE-branch.
Could yould please check and confirm (or not confirm) this by debugging ...?

When you try to convert the Item direct and it Returns an Error ... which kind of Error do you get and ... what is the Content of the Item ? I think this is the same Problem as above ...

Jamie888 8-Nov-16 1:14am

Yes sir, I have debugged my codes before. It indeed flow into the IF part. The value is GETDATE() which is in 11/8/2016 1.52 PM format. Then it comes to woStartDate.ToString("yyyy-MM-dd HH:mm:ss") part for conversion but nothing happen.

Ralf Meier 8-Nov-16 2:24am

see my Solution (2).

3 solutions

Solution 1

try to use this :

VB

woStartDate  =  DateTime.ParseExact(woStartDate , "MM/dd/yyyy h:mm:ss tt",
           Globalization.CultureInfo.InvariantCulture)

Posted 7-Nov-16 20:04pm

Mohd_Deeb

Solution 3

A DateTime variable doesn't have a format, it represents a point in time. It only gains a format when you convert it to a string. When you simply ask a DateTime variable to show itself as a string it chooses the format defined in the system settings of the OS, if you want it in a specific format you need to supply that format via ToString. The DateTime variable itself though doesn't have a format, what you are really seeing when you show it is its default representation.

Basically, you can't give DateTime a format, you can't give dates in SQL a format, you only give dates a format when you convert them to string so leave them as they are and convert them when you need to display them.

Posted 7-Nov-16 22:07pm

F-ES Sitecore

Comments

Ralf Meier 8-Nov-16 6:12am

Very good described ... but did you have had a look at my Solution ...?

Jamie888 8-Nov-16 20:14pm

Yes sir. Thank you for your explanation. It had clear my confusion. I have studied Mr. Meier(solution 2) solution and modified according to my need. It is working now.

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Ralf Meier · Accepted Answer · 2016-11-07T20:23:00

Sorry ... I read the code in the wrong way.
Try this code :

VB

Dim woStartDate As DateTime
dim myStartDate as string
While readerSQL.Read()
      If Not IsDBNull(readerSQL.Item("WOStartDate")) Then
         woStartDate = readerSQL.Item("WOStartDate") '11/8/2016 1.52 PM
         myStartDate = woStartDate.ToString("yyyy-MM-dd HH:mm:ss") '2016-11-08 13:52:21(expected result)
      Else
         myStartDate = DateTime.Now.tostring
      End If
End While

A Date or a DateTime is simply this.
Only a string could hold a different formatting ...