//Highlight relevant search results
        public string Highlight()
        {
            //Declaring a variable to hold search query
            string s = txtSearch.Text;
 
            if (s != null)
            {
                //string Search_Str = txtGrid.Text.ToString();  
 
                // Setup the regular expression    
                Regex RegExp = new Regex(s.Replace(" ", "|").Trim(), RegexOptions.IgnoreCase);
 
                //Highlight keywords by calling the delegate         
                //each time a keyword is found.        
                return
                   RegExp.Replace(s, new MatchEvaluator(ReplaceKeyWords));
                // Set the RegExp to null.            
                //RegExp = null;        
            }
            else
            {
                return s;
            }
        }
 
 
        // Method which helps find and highlight search results
        public string ReplaceKeyWords(Match m)
        {
 
            return "<span class=highlight>" + m.Value + "</span>";
        }