Fixes #380, added case correction for query string parameters in case…

… a user-entered query string contains keys that are not the same case as those that are configured in either preservedRouteParameters or route values.

src/MvcSiteMapProvider/MvcSiteMapProvider/Collections/Specialized/NameValueCollectionExtensions.cs

@@ -0,0 +1,24 @@
+using System.Collections.Generic;
+using System.Collections.Specialized;
+
+namespace MvcSiteMapProvider.Collections.Specialized
+{
+    /// <summary>
+    /// Provides extension methods for the <see cref="T:System.Collections.Specialized.NameValueCollection"/>.
+    /// </summary>
+    public static class NameValueCollectionExtensions
+    {
+        public static void AddWithCaseCorrection(this NameValueCollection nameValueCollection, string key, string value, IEnumerable<string> correctCaseKeyset)
+        {
+            var loweredKey = key.ToLowerInvariant();
+            foreach (var item in correctCaseKeyset)
+            {
+                if (item.ToLowerInvariant().Equals(loweredKey))
+                {
+                    // Add item with corrected case key
+                    nameValueCollection.Add(item, value);
+                }
+            }
+        }
+    }
+}

src/MvcSiteMapProvider/MvcSiteMapProvider/MvcSiteMapProvider.csproj

@@ -185,6 +185,7 @@
     <Compile Include="Collections\LockableList.cs" />
     <Compile Include="Collections\CacheableDictionary.cs" />
     <Compile Include="Collections\CacheableList.cs" />
+    <Compile Include="Collections\Specialized\NameValueCollectionExtensions.cs" />
     <Compile Include="Collections\Specialized\ReservedKeyException.cs" />
     <Compile Include="Collections\Specialized\SourceMetadataDictionary.cs" />
     <Compile Include="CompositeSiteMapNodeProvider.cs" />

src/MvcSiteMapProvider/MvcSiteMapProvider/SiteMapNode.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Collections.Specialized;
 using System.Web;
 using System.Web.Mvc;
 using System.Web.Routing;
@@ -620,7 +621,7 @@ protected virtual void PreserveRouteParameters()
             {
                 var requestContext = this.mvcContextFactory.CreateRequestContext();
                 var routeDataValues = requestContext.RouteData.Values;
-                var queryStringValues = requestContext.HttpContext.Request.QueryString;
+                var queryStringValues = this.GetCaseCorrectedQueryString(requestContext.HttpContext);
 
                 foreach (var item in this.PreservedRouteParameters)
                 {
@@ -642,6 +643,47 @@ protected virtual void PreserveRouteParameters()
             }
         }
 
+        /// <summary>
+        /// Gets a <see cref="T:System.Collections.Specialized.NameValueCollection"/> containing the query string
+        /// key value pairs for the passed in HTTP context. The casing of the keys corrected to be the same as the values that are 
+        /// configured either in the <see cref="P:RouteValues"/> dictionary or the <see cref="P:PreservedRouteParameters"/> collection.
+        /// </summary>
+        /// <param name="httpContext">The HTTP context.</param>
+        /// <returns>A <see cref="T:System.Collections.Specialized.NameValueCollection"/> containing the case-corrected 
+        /// key value pairs of the query string.</returns>
+        protected virtual NameValueCollection GetCaseCorrectedQueryString(HttpContextBase httpContext)
+        {
+            var queryStringValues = httpContext.Request.QueryString;
+            // Note: we must use the configured route values, rather than the RouteValue property to avoid an
+            // infinite loop.
+            var caseInsensitiveRouteKeys = new HashSet<string>(this.routeValues.Keys, StringComparer.InvariantCultureIgnoreCase);
+            var caseInsensitivePreservedRouteParameters = new HashSet<string>(this.PreservedRouteParameters, StringComparer.InvariantCultureIgnoreCase);
+            var result = new NameValueCollection();
+
+            foreach (var key in queryStringValues.AllKeys)
+            {
+                // A malformed URL could have a null key
+                if (key != null)
+                {
+                    if (caseInsensitivePreservedRouteParameters.Contains(key))
+                    {
+                        result.AddWithCaseCorrection(key, queryStringValues[key], caseInsensitivePreservedRouteParameters);
+                    }
+                    else if (caseInsensitiveRouteKeys.Contains(key))
+                    {
+                        result.AddWithCaseCorrection(key, queryStringValues[key], caseInsensitiveRouteKeys);
+                    }
+                    else
+                    {
+                        // If the value is not configured, add it to the dictionary with the original case.
+                        result.Add(key, queryStringValues[key]);
+                    }
+                }
+            }
+
+            return result;
+        }
+
         /// <summary>
         /// Flag to ensure the route values are only preserved from the current request a single time.
         /// </summary>
@@ -718,7 +760,7 @@ protected virtual IDictionary<string, object> MergeRouteValuesAndNamedQueryStrin
             var result = new Dictionary<string, object>(routeValues);
 
             // Add any query string values from the current context
-            var queryStringValues = httpContext.Request.QueryString;
+            var queryStringValues = this.GetCaseCorrectedQueryString(httpContext);
 
             // QueryString collection might contain nullable keys
             foreach (var key in queryStringValues.AllKeys)