Fix due to the modified Ext.cs

Example3/Chat.cs

@@ -13,7 +13,7 @@ namespace Example3 {
 
     private string getName()
     {
-      return QueryString.Exists("name")
+      return QueryString.Contains("name")
              ? QueryString["name"]
              : "anon#" + getNum();
     }

Example3/Echo.cs

@@ -8,7 +8,7 @@ namespace Example3 {
   {
     protected override void OnMessage(MessageEventArgs e)
     {
-      var msg = QueryString.Exists("name")
+      var msg = QueryString.Contains("name")
               ? String.Format("'{0}' returns to {1}", e.Data, QueryString["name"])
               : e.Data;
       Send(msg);