Date Calculations in PCL
I see that the GregorianCalendar class is not available in the C # Portable Class Library. I want to do some calendar calculations - how many months, weeks and days have passed between two dates.
Can I bet on myself?
Try Noda Time: http://nodatime.org/
It is a date / time library for .NET that has a portable version.
Usually, date / time operations can be performed directly from the DateTime construct. If you find something missing in the DateTime object, you can try including System.Globalization.dll in your application. Search in C: \ Windows \ Microsoft.NET and select the correct version.
The GregorianCalendar class itself suggests that its advantage over the DateTime class is ERA (BC, AD) support. It shares most of its code with DateTime.
Protip: If something isn't available in PCL and there isn't a good, tested library for that - why not try to port it to PCL? It doesn't have to be hard - I just looked at the source code .NET Framework
and it seems that it is not tightly coupled with anything outside of the PCL. Download Source Package GregorianCalendar