Merge pull request #143 from IDisposable/patch-1

Added contextualKeyBuilder optional argument to allow the key used for cachin...

src/Umbraco.Web/HtmlHelperRenderExtensions.cs

@@ -82,7 +82,8 @@ namespace Umbraco.Web
 			int cachedSeconds,
 			bool cacheByPage = false,
 			bool cacheByMember = false,
-			ViewDataDictionary viewData = null)
+			ViewDataDictionary viewData = null,
+			Func<object, ViewDataDictionary, string> contextualKeyBuilder = null)
 		{
 			var cacheKey = new StringBuilder(partialViewName);
 			if (cacheByPage)
@@ -97,7 +98,12 @@ namespace Umbraco.Web
 			{
 				var currentMember = Member.GetCurrentMember();
 				cacheKey.AppendFormat("m{0}-", currentMember == null ? 0 : currentMember.Id);
-			}			
+			}
+			if (contextualKeyBuilder != null)
+		    {
+		        var contextualKey = contextualKeyBuilder(model, viewData);
+		        cacheKey.Append("c{0}-", contextualKey);
+		    }
 			return ApplicationContext.Current.ApplicationCache.CachedPartialView(htmlHelper, partialViewName, model, cachedSeconds, cacheKey.ToString(), viewData);
 		}
 
@@ -813,4 +819,4 @@ namespace Umbraco.Web
 		#endregion
 
 	}
-}
+}