Need help with C# ParseExact syntax and moving between timezones

Okay, I have decided to let the magic of Stackoverflow work for me!

I have a date in the format: "Apr 18 2011 19:30 EDT" that I need开发者_JS百科 to push into a DateTime object in C#. One caviat, I also want to shift it to UTC too. Obivisouly when DST is over it'll come over as EST.

I know that I need a statement like:

 DateTime.ParseExact("Apr 18 2011 19:30 EDT",  "MMM DD yyyy something something ",  CultureInfo.InvariantCulture,  DateTimeStyles.None, out convertedDate);

But getting it over to UTC is above my knowlwedge level.

So in summary, I need:

1. To turn Apr 18 2011 19:30 EDT into a DateTime
2. Convert the EDT timezone to UTC time.
3. End up with a DateTime object.

What's the code, wizards?

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Well, if it's always going to be in Eastern Daylight Time, you can do something like:

// Parse string. We don't need escaping since E,D and T 
// are not considered special characters by ParseExact.
var dateTimeInEasternTime = DateTime.ParseExact("Apr 18 2011 19:30 EDT",
                                                "MMM dd yyyy HH:mm EDT",    
                                                CultureInfo.InvariantCulture);

// Convert from the relevant timezone to UTC.
var dateTimeInUTC = TimeZoneInfo.ConvertTime
                    (dateTimeInEasternTime,  
                     TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time"), 
                     TimeZoneInfo.Utc);

You can cache the TimeZoneInfo representing EST (which becomes EDT while daylight savings is on) to prevent the lookup.

If the string could end with a three letter code representing some arbitrary time-zone, it's going to be a lot more difficult since there are many conventions for them, none of which (AFAIK) are currently supported by .NET. Your best bet would be to first build a lookup from the code to the relevant TimeZoneInfo (perhaps through the Id property) after which you can do the conversion with TimeZoneInfo.ConvertTime as usual.

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I'm not sure exactly where you're getting hung up. It sounds like you have successfully parsed the string into a DateTime.

To convert the value to UTC, call the ToUniversalTime() method. Note that this will assume the current time value is relative to your system's current time zone.

ToUniversalTime() converts to a DateTime value.