1 files changed, 13 insertions, 0 deletions
diff --git a/src/DotNetOAuth/Messaging/ProtocolException.cs b/src/DotNetOAuth/Messaging/ProtocolException.cs
index 05ff340..d8b3d33 100644
--- a/src/DotNetOAuth/Messaging/ProtocolException.cs
+++ b/src/DotNetOAuth/Messaging/ProtocolException.cs
@@ -6,6 +6,7 @@
 
 namespace DotNetOAuth.Messaging {
 	using System;
+	using System.Collections.Generic;
 
 	/// <summary>
 	/// An exception to represent errors in the local or remote implementation of the protocol.
@@ -23,6 +24,11 @@ namespace DotNetOAuth.Messaging {
 		private Uri recipient;
 
 		/// <summary>
+		/// A cache for extra name/value pairs tacked on as data when this exception is sent as a message.
+		/// </summary>
+		private Dictionary<string, string> extraData = new Dictionary<string, string>();
+
+		/// <summary>
 		/// Initializes a new instance of the <see cref="ProtocolException"/> class.
 		/// </summary>
 		public ProtocolException() { }
@@ -148,6 +154,13 @@ namespace DotNetOAuth.Messaging {
 			}
 		}
 
+		/// <summary>
+		/// Gets the dictionary of additional name/value fields tacked on to this message.
+		/// </summary>
+		IDictionary<string, string> IProtocolMessage.ExtraData {
+			get { return this.extraData; }
+		}
+
 		#endregion
 
 		/// <summary>