Implementing Emoticons in C#

This piece of code shows you one way of replacing emoticons with their images. Remember the order of replacing the emotes matters! If you replace :) before :)), then you'll end up with a wrong image followed by the orphan ")".

Update [Oct 10, 2010]: A faster way (time complexity) of doing this would be to build a B-Tree and replace text in a single pass

 1 public string Emotify(string inputText)
 2 {
 3     #region Create Emote hashtable
 4     Hashtable htEmotes = new System.Collections.Hashtable(100);
 5     htEmotes.Add(":))", "21");
 6     htEmotes.Add(":)>-", "67");
 7     htEmotes.Add(":)", "1");
 8     htEmotes.Add(":-)", "1");
 9     htEmotes.Add(":((", "20");
10     htEmotes.Add(":(", "2");
11     // Add other Yahoo emotes
12     #endregion
13 
14 
15     StringBuilder sb = new StringBuilder(inputText.Length);
16 
17     for (int i = 0; i < inputText.Length; i++) {
18         string strEmote = string.Empty;
19         foreach (string emote in htEmotes.Keys) {
20             if (inputText.Length - i >= emote.Length &&
21                 emote.Equals(inputText.Substring(i, emote.Length),
22                 StringComparison.InvariantCultureIgnoreCase)) {
23 
24                 strEmote = emote;
25                 break;
26             }
27         }
28 
29         if (strEmote.Length != 0) {
30             sb.AppendFormat("<img src='images/{0}.gif' alt='{1}' />", 
31                 htEmotes[strEmote], strEmote);
32             i += strEmote.Length - 1;
33         }
34         else {
35             sb.Append(inputText[i]);
36         }
37     }
38     return sb.ToString();
39 }