From the MSDN documentation, it looks like NavigationContext.QueryString is an IDictionary<string, string>
. This means that your two variables will be of type string
.
Try casting your latitude and longitude variables to a type of double
.
var latitude = Convert.ToDouble(NavigationContext.QueryString["GeoLat"]);
var longtitude = Convert.ToDouble(NavigationContext.QueryString["GeoLong"]);