C# DateTime Conversion With Specific TimeZone

Install-Package TimeZoneConverter 
OR
Install-Package TimeZoneConverter -Version 5.0.0

localDateTime = DateTime.SpecifyKind(localDateTime, DateTimeKind.Unspecified)

DateTime localDateTime = DateTime.SpecifyKind(localDateTime, DateTimeKind.Unspecified);
TimeZoneInfo ut = TimeZoneInfo.FindSystemTimeZoneById(TZConvert.IanaToWindows(timezone));

TZConvert.IanaToWindows(timeZone)

So, we are using this IANA Database, so it stores the time zone as "America/New_York" for example, and we require something like this "Eastern Standard Time" which is used to convert by our c# functions.

So, we are using this function to translate the IANA time zone to our windows type, and it returns the string which is of windows time timezone.

var WindowsTimeZone=TZConvert.IanaToWindows(timeZone);
TimeZoneInfo ut=TimeZoneInfo.FindSystemTimeZoneById(WindowsTimeZone);

Now, the first line is the same to convert IANA timezone to windows and store to variable.

Now the TimeZoneInfo. FineSystemTimeZoneById is taking the windows type timezone as argument and matches it with the local system's key and returns an object of the information about the offset, current time and many more information. Which can be used by the other functions.

In short, this functions returns us information about the windows type timezone by key which we have passed as argument.

var WindowsTimeZone=TZConvert.IanaToWindows(timeZone);
TimeZoneInfo ut=TimeZoneInfo.FindSystemTimeZoneById(WindowsTimeZone);
DateTime localDateTime = TimeZoneInfo.ConvertTimeToUtc(localDateTime, ut);

Now, the line 3 in the above code "TimeZoneInfo. ConvertTimeToUtc" is going to take the windows type timezone object and take the necessary information about the timezone like the Offset and add/subtract it with the localDateTime and returns us a date which is in the UTC with respect to the timezone which we have specified as second argument.

Now, let's just create a function for that, which takes the date time and timezone and returns us a time in UTC with respect to the specified timezone.

public static DateTime ConvertLocalToUTCwithTimeZone(DateTime localDateTime,string timezone)
{
    localDateTime = DateTime.SpecifyKind(localDateTime, DateTimeKind.Unspecified);
    TimeZoneInfo ut = TimeZoneInfo.FindSystemTimeZoneById(TZConvert.IanaToWindows(timezone));
    return TimeZoneInfo.ConvertTimeToUtc(localDateTime, ut);
}

UTC To Specific Time Zone

Now, we have checked with the functions which returns us the UTC date time with respect to the Time Zone but now what if we want to get the date time from the UTC with respect to the timezone. So, let's check out the following code:

var WindowsTypeTimeZone = TZConvert.IanaToWindows(timeZone);
var TimeZoneInfo=TimeZoneInfo.FindSystemTimeZoneById(WindowsTypeTimeZone);
TimeZoneInfo.ConvertTimeFromUtc(Date,TimeZoneInfo);

Now, As we have already checked, the code which returns us the UTC time. So, as per that, we have a code to get the date time for specific timezone from UTC is similar to that.

On First line, we are translating the IANA type timezone to windows type timezone.

In the second line, we are getting the information about the windows type timezone.

Now in the third line we have directly converted the UTC Date time to particular date time with respect to the timezone which we have specified.

NOTE : To Convert time From UTC we have not specified any kind as we know this is the UTC date time from which we have to convert to specific timezone.

Let's just create a function for the same, which we can reuse in our project.

public static DateTime getLocaltimeFromUniversal(DateTime utcDateTime, string timeZone)
{
    return TimeZoneInfo.ConvertTimeFromUtc(utcDateTime, 
    TimeZoneInfo.FindSystemTimeZoneById(TZConvert.IanaToWindows(timeZone)));
}

Convert DateTime to Specific Time Zone

Now, If we want to convert time to specific time, we can reuse both function and create a new function which directly returns you the time of the specific timezone from the particular timezone of time.

Let's say, I have a time in IST and I don't want to handle this different time in the code and want the single function call which returns me the time of specific time.

public static DateTime GetTimeofTimeZone(localDateTime,FromTimeZone,ToTimeZone)
{
     DateTime utcTime=ConvertLocalToUTCwithTimeZone(localDateTime,FromTimeZone);
	   return getLocaltimeFromUniversal(utcTime,ToTimeZone);
}

Now, What the above function does is taking the three arguments on is the DateTime which you want to convert, the timezone of the date time, and third is the time zone in which you convert your date time.

To Calculate all this,

• First we call the function to get UTC time with time zone and date we got
• Secondly, we will call the function to local time with the UTC date which got from the first function call and timezone in which we want to convert
• in result, it returns me the date time in resultant time zone.

Create Class For Class Library

Now, If we want to make it as the class library, and then we have to reuse in the different projects then you can use the following class and import as the class library and debug it and prepare a DLL of it, and you can import that DLL and reuse it in your different projects.

using System;
using TimeZoneConverter;

namespace TimeZoneHelper
{
    public static class TimezoneHelper
    {
        public static DateTime getLocaltimeFromUniversal(DateTime utcDateTime, string timeZone)
        {
            return TimeZoneInfo.ConvertTimeFromUtc(utcDateTime, 
            TimeZoneInfo.FindSystemTimeZoneById(TZConvert.IanaToWindows(timeZone)));
        }
        public static DateTime ConvertLocalToUTCwithTimeZone(DateTime localDateTime,string timezone)
		{
			localDateTime = DateTime.SpecifyKind(localDateTime, DateTimeKind.Unspecified);
			return TimeZoneInfo.ConvertTimeToUtc(localDateTime, 
              TimeZoneInfo.FindSystemTimeZoneById(TZConvert.IanaToWindows(timezone)));
		}
    }
}

I also have attached one zip file with this Article, which contains the above class file and one DLL file. A DLL file is a class library file which you can use with different project as reference.

I hope this is helpful to you, for you to make your application dynamic.