//initialize a dictionary with keys and values.  Dictionary<int, string> plants = new Dictionary<int, string>() {    {1,"Speckled Alder"},    {2,"Apple of Sodom"},    {3,"Hairy Bittercress"},    {4,"Pennsylvania Blackberry"},    {5,"Apple of Sodom"},    {6,"Water Birch"},    {7,"Meadow Cabbage"},    {8,"Water Birch"}  };   Response.Write("<b>dictionary elements........ www.49028c.com </b><br />");     //loop dictionary all elements  foreach (KeyValuePair<int, string> pair in plants) {  Response.Write(pair.Key + "....."+ pair.Value+"<br />");}   //find dictionary duplicate values. var duplicateValues = plants.GroupBy(x => x.Value).Where(x => x.Count() > 1); Response.Write("<br /><b>dictionary duplicate values..........</b><br />"); //loop dictionary duplicate values only      foreach(var item in duplicateValues) {  Response.Write(item.Key+"<br />");}