Added exception for nodes that are configured with the same key in bo…

…th PreservedRouteParameters and RouteValues, which is checked when the node is added to the SiteMap.

src/MvcSiteMapProvider/MvcSiteMapProvider/Resources/Messages.resx

@@ -216,4 +216,11 @@
   <data name="ReflectionSiteMapBuilderRootKeyAmbiguous" xml:space="preserve">
     <value>There is more than one MvcSiteMapNodeAttribute declared without a parent key. The ParentKey property must be set for all (or all but 1) MvcSiteMapNodeAttribute in the application.</value>
   </data>
+  <data name="SiteMapNodeSameKeyInRouteValueAndPreservedRouteParameter" xml:space="preserve">
+    <value>The node with key '{0}' has '{1}' configured in both RouteValues and PreservedRouteParameters, which is not allowed. 
+
+PreservedRouteParameters always copies the route value from the current HTTP request which would overwrite your configured RouteValue in every case. Either remove '{1}' from PreservedRouteParameters or as a configured RouteValue.
+
+Alternatively, if you are configuring the node in XML and intend to use '{1}' as a custom attribute, use the 'MvcSiteMapProvider_AttributesToIgnore' configuration setting to ensure '{1}' is not automatically added to RouteValues. If using external DI, this setting is injected into the constructor of 'SiteMapXmlReservedAttributeNameProvider'.</value>
+  </data>
 </root>

src/MvcSiteMapProvider/MvcSiteMapProvider/SiteMap.cs

@@ -102,6 +102,12 @@ public virtual void AddNode(ISiteMapNode node)
         /// </exception>
         public virtual void AddNode(ISiteMapNode node, ISiteMapNode parentNode)
         {
+            if (node == null)
+            {
+                throw new ArgumentNullException("node");
+            }
+            ThrowIfSiteMapNodeRoutingConfigInvalid(node);
+
             // Avoid issue with url table not clearing correctly.
             if (this.FindSiteMapNode(node.Url) != null)
             {
@@ -763,6 +769,18 @@ protected virtual ISiteMapNode ReturnNodeIfAccessible(ISiteMapNode node)
             return null;
         }
 
+        protected virtual void ThrowIfSiteMapNodeRoutingConfigInvalid(ISiteMapNode node)
+        {
+            if (node.PreservedRouteParameters.Count > 0)
+            {
+                foreach (var key in node.PreservedRouteParameters)
+                {
+                    if (node.RouteValues.ContainsKey(key))
+                        throw new MvcSiteMapException(String.Format(Resources.Messages.SiteMapNodeSameKeyInRouteValueAndPreservedRouteParameter, node.Key, key));
+                }
+            }
+        }
+
         #endregion
 
     }