Formatting DateTime with milliseconds and retaining regional settings

That's an interesting problem since you don't necessarily know where the time is. What I would probably do is get the current culture's DateTimeFormatInfo. Within here is the FullDateTimePattern which contains the format string that will be used. However it is just a concat of LongDatePattern and LongTimePattern so I'd probably take LongTimePattern, append the millisecond specifier to the time (by searching for the s letters, and then use that to format the value. Honestly how much this is doable directly in an SSRS expression is limited. Therefore I'd probably put this in a function that SSRS calls.

Perhaps something like this (untested):

   Public Function MyFormatDateTime ( ByVal value as DateTime) As String  
      Dim culture = CultureInfo.CurrentCulture  
     
      Dim format = culture.LongTimePattern  
      Dim index = format.LastIndexOf("s")  
      If index >= 0 Then  
         format = format.Insert(index, "fff")  
      End If  
     
      Return value.ToString(culture.LongDatePattern) & " " & value.ToString(format)  
   End Function  

Hi @IH ,
You would need to FORMAT the field with the little known fff for the milliseconds. You would also need to use tt for the AM or PM.

You can use the FORMAT function to format it:

=FORMAT(NOW(), "MM/dd/yyyy hh:mm:ss.fff tt")  

Or you can use the FORMAT property of the text box.

Preview:

Best Regards,
Joy

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None of the suggestions would work. In the end, my solution was to just search the string and replace AM or PM with ".fff 'AM'" or ".fff 'PM'". This seems to work, but not ideal.