Removed duplicated ToFriendlyEmpty() methods and introduced an equivalent extension method. Changed <empty> to [Empty] to avoid HTML encoding problems.

src/Orchard.Web/Modules/Orchard.AuditTrail/Helpers/StringExtensions.cs

@@ -1,4 +1,5 @@
 using System;
+using Orchard.Localization;
 
 namespace Orchard.AuditTrail.Helpers {
     public static class StringExtensions {
@@ -12,5 +13,9 @@ namespace Orchard.AuditTrail.Helpers {
 
             return i;
         }
+
+        public static string OrIfEmpty(this string value, LocalizedString emptyString) {
+            return String.IsNullOrWhiteSpace(value) ? emptyString.Text : value;
+        }
     }
 }

src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-PartSettingsUpdated.SummaryAdmin.cshtml

@@ -3,11 +3,6 @@
 @{
     Style.Include("audittrail-contenttype-event.css");
 }
-@functions {
-    string ToFriendlyEmpty(string value) {
-        return String.IsNullOrWhiteSpace(value) ? Html.Encode(T("<empty>").Text) : value;
-    }
-}
 @{
     var eventData = (IDictionary<string, object>)Model.EventData;
     var contentPartName = eventData.Get<string>("ContentPartName");
@@ -18,7 +13,7 @@
     <ul>
         @foreach (var setting in diff) {
             <li>
-                @T("<strong>{0}</strong> was changed from <strong>{1}</strong> to <strong>{2}</strong>.", setting.Key, ToFriendlyEmpty(setting.Value.OldValue), ToFriendlyEmpty(setting.Value.NewValue))
+                @T("<strong>{0}</strong> was changed from <strong>{1}</strong> to <strong>{2}</strong>.", setting.Key, setting.Value.OldValue.OrIfEmpty(T("[Empty]")), setting.Value.NewValue.OrIfEmpty(T("[Empty]")))
             </li>
         }
     </ul>

src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentPart-PartSettingsUpdated.cshtml

@@ -3,11 +3,6 @@
 @{
     Style.Include("audittrail-contenttype-event.css");
 }
-@functions {
-    string ToFriendlyEmpty(string value) {
-        return String.IsNullOrWhiteSpace(value) ? Html.Encode(T("<empty>").Text) : value;
-    }
-}
 @{
     var eventData = (IDictionary<string, object>)Model.EventData;
     var contentPartName = eventData.Get<string>("ContentPartName");
@@ -27,8 +22,8 @@
             @foreach (var setting in diff) {
                 <tr>
                     <td>@setting.Key</td>
-                    <td>@ToFriendlyEmpty(setting.Value.OldValue)</td>
+                    <td>@setting.Value.OldValue.OrIfEmpty(T("[Empty]"))</td>
-                    <td>@ToFriendlyEmpty(setting.Value.NewValue)</td>
+                    <td>@setting.Value.NewValue.OrIfEmpty(T("[Empty]"))</td>
                 </tr>
             }
         </tbody>

src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-FieldSettingsUpdated.SummaryAdmin.cshtml

@@ -3,11 +3,6 @@
 @{
     Style.Include("audittrail-contenttype-event.css");
 }
-@functions {
-    string ToFriendlyEmpty(string value) {
-        return String.IsNullOrWhiteSpace(value) ? Html.Encode(T("<empty>").Text) : value;
-    }
-}
 @{
     var eventData = (IDictionary<string, object>) Model.EventData;
     var contentTypeName = eventData.Get<string>("ContentTypeName");
@@ -22,7 +17,7 @@
     <ul>
         @foreach (var setting in diff) {
             <li>
-                @T("<strong>{0}</strong> was changed from <strong>{1}</strong> to <strong>{2}</strong>.", setting.Key, ToFriendlyEmpty(setting.Value.OldValue), ToFriendlyEmpty(setting.Value.NewValue))
+                @T("<strong>{0}</strong> was changed from <strong>{1}</strong> to <strong>{2}</strong>.", setting.Key, setting.Value.OldValue.OrIfEmpty(T("[Empty]")), setting.Value.NewValue.OrIfEmpty(T("[Empty]")))
             </li>
         }
     </ul>

src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-FieldSettingsUpdated.cshtml

@@ -3,11 +3,6 @@
 @{
     Style.Include("audittrail-contenttype-event.css");
 }
-@functions {
-    string ToFriendlyEmpty(string value) {
-        return String.IsNullOrWhiteSpace(value) ? T("<empty>").Text : value;
-    }
-}
 @{
     var eventData = (IDictionary<string, object>) Model.EventData;
     var contentTypeName = eventData.Get<string>("ContentTypeName");
@@ -31,8 +26,8 @@
             @foreach (var setting in diff) {
                 <tr>
                     <td>@setting.Key</td>
-                    <td>@ToFriendlyEmpty(setting.Value.OldValue)</td>
+                    <td>@setting.Value.OldValue.OrIfEmpty(T("[Empty]"))</td>
-                    <td>@ToFriendlyEmpty(setting.Value.NewValue)</td>
+                    <td>@setting.Value.NewValue.OrIfEmpty(T("[Empty]"))</td>
                 </tr>
             }
         </tbody>

src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-PartSettingsUpdated.SummaryAdmin.cshtml

@@ -3,11 +3,6 @@
 @{
     Style.Include("audittrail-contenttype-event.css");
 }
-@functions {
-    string ToFriendlyEmpty(string value) {
-        return String.IsNullOrWhiteSpace(value) ? Html.Encode(T("<empty>").Text) : value;
-    }
-}
 @{
     var eventData = (IDictionary<string, object>) Model.EventData;
     var contentTypeName = eventData.Get<string>("ContentTypeName");
@@ -19,7 +14,7 @@
     <ul>
         @foreach (var setting in diff) {
             <li>
-                @T("<strong>{0}</strong> was changed from <strong>{1}</strong> to <strong>{2}</strong>.", setting.Key, ToFriendlyEmpty(setting.Value.OldValue), ToFriendlyEmpty(setting.Value.NewValue))
+                @T("<strong>{0}</strong> was changed from <strong>{1}</strong> to <strong>{2}</strong>.", setting.Key, setting.Value.OldValue.OrIfEmpty(T("[Empty]")), setting.Value.NewValue.OrIfEmpty(T("[Empty]")))
             </li>
         }
     </ul>

src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-PartSettingsUpdated.cshtml

@@ -3,11 +3,6 @@
 @{
     Style.Include("audittrail-contenttype-event.css");
 }
-@functions {
-    string ToFriendlyEmpty(string value) {
-        return String.IsNullOrWhiteSpace(value) ? Html.Encode(T("<empty>").Text) : value;
-    }
-}
 @{
     var eventData = (IDictionary<string, object>) Model.EventData;
     var contentTypeName = eventData.Get<string>("ContentTypeName");
@@ -28,8 +23,8 @@
             @foreach (var setting in diff) {
                 <tr>
                     <td>@setting.Key</td>
-                    <td>@ToFriendlyEmpty(setting.Value.OldValue)</td>
+                    <td>@setting.Value.OldValue.OrIfEmpty(T("[Empty]"))</td>
-                    <td>@ToFriendlyEmpty(setting.Value.NewValue)</td>
+                    <td>@setting.Value.NewValue.OrIfEmpty(T("[Empty]"))</td>
                 </tr>
             }
         </tbody>

src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-TypeSettingsUpdated.SummaryAdmin.cshtml

@@ -3,23 +3,17 @@
 @{
     Style.Include("audittrail-contenttype-event.css");
 }
-@functions {
-    string ToFriendlyEmpty(string value) {
-        return String.IsNullOrWhiteSpace(value) ? Html.Encode(T("<empty>").Text) : value;
-    }
-}
 @{
     var eventData = (IDictionary<string, object>) Model.EventData;
     var contentTypeName = eventData.Get<string>("ContentTypeName");
     var diff = (DiffDictionary<string, string>) Model.Diff;
 }
-
 <section class="audittrail-contenttype-event">
     @T("Settings for the content type <strong>{0}</strong> were changed:", contentTypeName)
     <ul>
         @foreach (var setting in diff) {
             <li>
-                @T("<strong>{0}</strong> was changed from <strong>{1}</strong> to <strong>{2}</strong>.", setting.Key, ToFriendlyEmpty(setting.Value.OldValue), ToFriendlyEmpty(setting.Value.NewValue))
+                @T("<strong>{0}</strong> was changed from <strong>{1}</strong> to <strong>{2}</strong>.", setting.Key, setting.Value.OldValue.OrIfEmpty(T("[Empty]")), setting.Value.NewValue.OrIfEmpty(T("[Empty]")))
             </li>
         }
     </ul>

src/Orchard.Web/Modules/Orchard.AuditTrail/Views/AuditTrailEvent-ContentType-TypeSettingsUpdated.cshtml

@@ -3,11 +3,6 @@
 @{
     Style.Include("audittrail-contenttype-event.css");
 }
-@functions {
-    static string ToFriendlyEmpty(string value) {
-        return String.IsNullOrWhiteSpace(value) ? "<empty>" : value;
-    }
-}
 @{
     var eventData = (IDictionary<string, object>) Model.EventData;
     var contentTypeName = eventData.Get<string>("ContentTypeName");
@@ -27,8 +22,8 @@
             @foreach (var setting in diff) {
                 <tr>
                     <td>@setting.Key</td>
-                    <td>@ToFriendlyEmpty(setting.Value.OldValue)</td>
+                    <td>@setting.Value.OldValue.OrIfEmpty(T("[Empty]"))</td>
-                    <td>@ToFriendlyEmpty(setting.Value.NewValue)</td>
+                    <td>@setting.Value.NewValue.OrIfEmpty(T("[Empty]"))</td>
                 </tr>
             }
         </tbody>