c# - What is the best way to convert a list of dates so it displays in groups if it contains consecutive days? -

i have list of dates

 var list = new list<datetime>();  list.add(new datetime(2014, 1,1);  list.add(new datetime(2014, 1,2);  list.add(new datetime(2014, 1,3);  list.add(new datetime(2014, 1,5);  list.add(new datetime(2014, 1,6);  list.add(new datetime(2014, 1,11); 

and dates consecutive. want group consecutive dates , render on ui as:

"jan 1-3, 2015; jan 5-6, 2015; jan 11, 2015" 

what correct way lis t transformation? without . this:

 var display = string.join(";", list.select(r=>r.tostring("dd-mmm-yyyy")); 

void main() {     var list = new list<datetime>();     list.add(new datetime(2014, 1, 1));     list.add(new datetime(2014, 1, 2));     list.add(new datetime(2014, 1, 3));     list.add(new datetime(2014, 1, 5));     list.add(new datetime(2014, 1, 6));     list.add(new datetime(2014, 1, 11));      string output = string.join("; ", getranges(list).select(formatrange));      console.writeline(output);     // jan 1–3, 2014; jan 5–6, 2014; jan 11, 2014 }  private string formatrange (daterange range) {     if (range.start.year != range.end.year)         return range.start.tostring("mmm d, yyyy") + " – " + range.end.tostring("mmm d, yyyy");     else if (range.start.month != range.end.month)         return range.start.tostring("mmm d") + " – " + range.end.tostring("mmm d, yyyy");     else if (range.start.day != range.end.day)         return range.start.tostring("mmm d") + "–" + range.end.tostring("d, yyyy");     else         return range.start.tostring("mmm d, yyyy"); }  private list<daterange> getranges (ienumerable<datetime> dates) {     list<daterange> ranges = new list<daterange>();     daterange current = null;     datetime? previous = null;      foreach (datetime date in dates)     {         if (!previous.hasvalue)             current = new daterange() { start = date };         else if ((date - previous.value).days > 1)         {             current.end = previous.value;             ranges.add(current);             current = new daterange() { start = date };         }            previous = date;     }      if (previous.hasvalue)     {         current.end = previous.value;         ranges.add(current);     }      return ranges; }  public class daterange {     public datetime start { get; set; }     public datetime end { get; set; } }