In one part of my code I convert from decimal coordinates to degrees/minutes/seconds and I use this:
double coord = 59.345235;
int sec = (int)Math.Round(coor
CoordinateSharp is available as a Nuget package and can handle Coordinate conversions for you. It even does UTM/MGRS conversion and provides solar/lunar times relative to the input location. It's really easy to use!
Coordinate c = new Coordinate(40.465, -75.089);
//Display DMS Format
c.FormatOptions.Format = CoordinateFormatType.Degree_Minutes_Seconds;
c.ToString();//N 40º 27' 54" W 75º 5' 20.4"
c.Latitude.ToString();//N 40º 27' 54"
c.Latitude.ToDouble();//40.465
Coordinate properties are iObservable as as well. So if you change a latitude minute value for example, everything else will update.