2006-06-21 Gonzalo Paniagua Javier <gonzalo@ximian.com>

* glade/HandlerNotFoundExeception.cs:
	* glade/XML.custom: provide a better error when the signature of a
	handler does not match the one of the event.


svn path=/trunk/gtk-sharp/; revision=61911

ChangeLog

@@ -1,3 +1,9 @@
+2006-06-21 Gonzalo Paniagua Javier <gonzalo@ximian.com>
+
+	* glade/HandlerNotFoundExeception.cs:
+	* glade/XML.custom: provide a better error when the signature of a
+	handler does not match the one of the event.
+
 2006-05-10  Mike Kestner  <mkestner@novell.com>
 
 	* bootstrap-2.10 : strap for the new 2.9.0 API.

glade/HandlerNotFoundExeception.cs

@@ -52,6 +52,17 @@ namespace Glade {
 			this.delegate_type = delegate_type;
 		}				 
 
+		public HandlerNotFoundException (string message, string handler_name, string signal_name, 
+						 EventInfo evnt, Type delegate_type)
+			: base ((message != null) ? message : "No handler " + handler_name + " found for signal " + signal_name,
+				null)
+		{
+			this.handler_name = handler_name;
+			this.signal_name = signal_name;
+			this.evnt = evnt;
+			this.delegate_type = delegate_type;
+		}				 
+
 		protected HandlerNotFoundException (SerializationInfo info, StreamingContext context)
 			: base (info, context)
 		{

glade/XML.custom

@@ -257,12 +257,69 @@
 	
 						if (!connected) 
 						{
-							throw new HandlerNotFoundException (handler_name, signal_name, ei, delegate_type);
+							string msg = ExplainError (ei.Name, delegate_type, handler_type, handler_name);
+							throw new HandlerNotFoundException (msg, handler_name, signal_name, ei, delegate_type);
 						}
 					}
 				}
 	
 			}
+
+			static string GetSignature (System.Reflection.MethodInfo method)
+			{
+				if (method == null)
+					return null;
+
+				System.Reflection.ParameterInfo [] parameters = method.GetParameters ();
+				System.Text.StringBuilder sb = new System.Text.StringBuilder ();
+				sb.Append ('(');
+				foreach (System.Reflection.ParameterInfo info in parameters) {
+					sb.Append (info.ParameterType.ToString ());
+					sb.Append (',');
+				}
+				if (sb.Length != 0)
+					sb.Length--;
+
+				sb.Append (')');
+				return sb.ToString ();
+			}
+
+			static string GetSignature (Type delegate_type)
+			{
+				System.Reflection.MethodInfo method = delegate_type.GetMethod ("Invoke");
+				return GetSignature (method);
+			}
+
+			const System.Reflection.BindingFlags flags = System.Reflection.BindingFlags.NonPublic |
+							System.Reflection.BindingFlags.Public |
+							System.Reflection.BindingFlags.Static |
+							System.Reflection.BindingFlags.Instance;
+			static string GetSignature (Type klass, string method_name)
+			{
+				try {
+					System.Reflection.MethodInfo method = klass.GetMethod (method_name, flags);
+					return GetSignature (method);
+				} catch {
+					// May be more than one method with that name and none matches
+					return null;
+				}
+			}
+
+			static string ExplainError (string event_name, Type deleg, Type klass, string method)
+			{
+				if (deleg == null || klass == null || method == null)
+					return null;
+
+				System.Text.StringBuilder sb = new System.Text.StringBuilder ();
+				string expected = GetSignature (deleg);
+				string actual = GetSignature (klass, method);
+				if (actual == null)
+					return null;
+					sb.AppendFormat ("The handler for the event {0} should take '{1}', " +
+						"but the signature of the provided handler ('{2}') is '{3}'\n",
+						event_name, expected, method, actual);
+				return sb.ToString ();
+			}
 	
 			System.Reflection.MemberFilter signalFilter = new System.Reflection.MemberFilter (SignalFilter);