Develop Reference

Not able to convert a string value to Date time including milliseconds

I have a string value which I need to convert to DateTime
currentDate="29-APR-17 03.42.06.410000 PM"
I tried the below statement, but its throwing error:
DateTime originalDate = DateTime.Parse(currentDate);
DateTime originalDate = Convert.ToDateTime(currentDate);
I even followed this link "https://msdn.microsoft.com/en-us/library/bb882581(v=vs.110).aspx"
but is is also not helping
Moreover, the information provided in Stackoverflow was not helping as I am always facing the error String was not recognized as a valid DateTime.

The DateTime.ParseExact should solve the formatting like this:
DateTime originalDate = DateTime.ParseExact(currentDate, "dd-MMM-yy hh.mm.ss.ffffff tt", CultureInfo.InvariantCulture, DateTimeStyles.None);
or if time part are separated with colons:
DateTime.ParseExact(currentDateWithColons, "dd-MMM-yy hh:mm:ss.ffffff tt", CultureInfo.InvariantCulture, DateTimeStyles.None);
Both dots and colons producing the same result using Console.WriteLine(originalDate.ToString("dd/MM/yyyy hh:mm:ss.ffffff tt")):
29/04/2017 03:42:06.410000 PM
Working example: .NET Fiddle Demo

try below code
string currentDate="29-APR-17 03:42:06.410000 PM"
DateTime originalDate = DateTime.Parse(currentDate);
originalDate = Convert.ToDateTime(currentDate);
Console.WriteLine(originalDate.ToString("dd-MM-yyyy-fff"));
you were using wrong format use : instead of . in time.
changed "29-APR-17 03.42.06.410000 PM" to "29-APR-17 03:42:06.410000 PM"

string currentDate = "29-APR-17 03:42:06.410000 PM";
var date = DateTime.ParseExact(currentDate, "dd-MMM-yy hh:mm:ss.ffffff tt", CultureInfo.InvariantCulture);

Convert dd/MM/yyyy HH:mm tt to MM/dd/yyyy HH:mm tt in C#

I want to convert string as : "25/12/2017 4:00 PM" to "12/25/2017 4:00 PM". My code :
var TDXRSC = "25/12/2017 4:00 PM";
DateTime.ParseExact(TDXRSC, "dd/MM/yyyy hh:mm tt", CultureInfo.InvariantCulture);
But it's not working.

The issue is your date format expected is dd/MM/yyyy hh:mm tt but the reference date only has a single digit hour 4. You are probably better off not expect leading zeros for days, months or hours.
Try..
var TDXRSC = "25/12/2017 4:00 PM";
var input = DateTime.ParseExact(TDXRSC, "dd/MM/yyyy h:mm tt", CultureInfo.InvariantCulture);
This will also still parse 2 digit hours. So var TDXRSC = "25/12/2017 12:00 PM"; will still parse correctly.

var TDXRSC = "25/12/2017 4:00 PM";
var input = DateTime.ParseExact(TDXRSC, "dd/MM/yyyy h:mm tt", CultureInfo.InvariantCulture);
var output = input.ToString("MM/dd/yyyy h:mm tt");
When you call ParseExact you're telling the compiler what format the incoming date is. You can then use ToString() method to provide a format for a string representation of the parsed date.

Hope that .TryParseExtract will be more safe to use for conversion, use like the following:
var dateString = "25/12/2017 4:00 PM";
DateTime inputDate;
if(DateTime.TryParseExact(dateString, "dd/MM/yyyy h:mm tt", CultureInfo.InvariantCulture, DateTimeStyles.None, out inputDate))
{
var output = inputDate.ToString("MM/dd/yyyy hh:mm tt");
Console.WriteLine(output);
}
else
{
Console.WriteLine("Conversion failed");
}
Working Example

var TDXRSC = "25/12/2017 4:00 PM";
DateTime date = Convert.ToDateTime(TDXRSC);
string Format = date.ToString("MM/dd/yyyy h:mm tt");

How to find exact format of a date string?

I need to know exact date format that will perse the string 16-Aug-78 12:00:00 AM. I have tried various string like "ss-MMM-yy hh:mm:ss". Is there any way for finding it to converting to any general format. I am using CultureInfo.InvariantCulture class.

Your string format is wrong. It has to match your string format exactly. You can use dd-MMM-yy hh:mm:ss tt format instead.
Here an example in LINQPad.
string s = "16-Aug-78 12:00:00 AM";
var date = DateTime.ParseExact(s, "dd-MMM-yy hh:mm:ss tt",
CultureInfo.InvariantCulture);
date.Dump();
Custom Date and Time Format Strings
Or, since dd-MMM-yy hh:mm:ss tt is a standart date and time format for InvariantCulture, you can directly DateTime.Parse method like;
string s = "16-Aug-78 12:00:00 AM";
var date = DateTime.Parse(s, CultureInfo.InvariantCulture);
date.Dump();
Here a demonstration.
Is there any way for finding it to converting to any general format?
There is no way to get format of a string except you create your own formatting. Only you can know what is your string format exactly, computer can't.
For example; 01/02/2014 can be 1 February 2014 or 2 January 2014 depends on which custom format you can parse it.

Try as below
var dstring = "16-Aug-78 12:00:00 AM";
DateTime result;
var matchingCulture = CultureInfo.GetCultures(CultureTypes.AllCultures).FirstOrDefault(ci => DateTime.TryParse(dstring, ci, DateTimeStyles.None, out result))

You have wrong format string, you are using ss for day it should be dd. This article Custom Date and Time Format Strings explains what you need for custom format.
Use
"dd-MMM-yy hh:mm:ss tt"
Instead of
"ss-MMM-yy hh:mm:ss"
You can use DateTime.ParseExact to parse the string.
DateTime dt = DateTime.ParseExact("16-Aug-78 12:00:00 AM", "dd-MMM-yy hh:mm:ss tt", CultureInfo.InvariantCulture, DateTimeStyles.None);

You can try with DateTime.TryParseExact():
string strDate = "16-Aug-78 12:00:00 AM";
DateTime datDate;
if(DateTime.TryParseExact(strDate , new string[] {"dd-MMM-yy hh:mm:ss tt" },
System.Globalization.CultureInfo.InvariantCulture,
System.Globalization.DateTimeStyles.None, out datDate))
{
Console.WriteLine(datDate);
}
else
{
Console.WriteLine("Error in datetime format");
}

date format issue, String was not recognized as a valid DateTime

I am getting dates from database and i want to convert the date in dd/MM/yyyy format,
I am trying this but it gives me error "String was not recognized as a valid DateTime."
DateTime pDate = DateTime.ParseExact("05/28/2013 12:00:00 AM", "dd/MM/yyyy", CultureInfo.InvariantCulture);
Please let me know how i can convert into dd/MM/yyyy format?
Thanks

try with MM/dd/yyyy hh:mm:ss tt instead of dd/MM/yyyy
if you use DateTime.ParseExact The format of the string representation must match a specified format exactly or an exception is thrown.
if you need only the date
DateTime pDate = DateTime.ParseExact("05/28/2013 12:00:00 AM", "MM/dd/yyyy hh:mm:ss tt", CultureInfo.InvariantCulture);
var dateOnly= pDate.ToString("dd/MM/yyyy");
As per your comment, database contain data with Type 'Date', So you can read it directly as DateTime. You can convert to string by calling ToString with the expected Format.

2 steps:
DateTime pDate = DateTime.ParseExact("05/28/2013 12:00:00 AM", "MM/dd/yyyy hh:mm:ss", CultureInfo.InvariantCulture);
return pDate.ToString("dd/MM/yyyy");

DateTime d = DateTime.Parse(
"15/12/2019",
new System.Globalization.CultureInfo("pt-BR"));
refer https://blog.submain.com/string-was-not-recognized-as-valid-datetime/

String to DateTime format

I am trying to convert 10/10/2010 12:00:00 a.m. to dateTime . I am using this...
DateTime.ParseExact(item.Birthey, "dd/MM/yyyy hh:mm:ss tt", null);
But I get String was not recognized as a valid DateTime.
What is the correct way to do this?

Just simply try the Parse or ParseExact with manipulation of string command like:
string stringDate= "10/10/2010 12:00:00 P.M.";
var myDate = DateTime.Parse(stringDate.Replace(".", ""));
You may also try the following code sample if, the raw data that you get has "a.m." ending in it. Just replace that characters:
string stringDate= "10/10/2010 12:00:00 a.m.";
DateTime result = DateTime.ParseExact(stringDate.Replace(".", ""),
"dd/MM/yyyy hh:mm:ss tt", null);

Try instead
DateTime.ParseExact("10/10/2010 12:00:00 am", "dd/MM/yyyy hh:mm:ss tt", null).Dump();
the . in a.m. are creating the problems. You can use Replace to remove the . (as in your date format . can only appear in a.m., or p.m.
DateTime.ParseExact("10/10/2010 12:00:00 a.m.".Replace(".",""), "dd/MM/yyyy hh:mm:ss tt", null).Dump();

Try to specify CultureInfo.InvariantCulture instead of null. In your case it uses CultureInfo.CurrentCulture.