From e2746604a16e9c0b08a1756ca6be1673ef8a9ccf Mon Sep 17 00:00:00 2001
From: Kenn Jacobsen <post@kennjacobsen.dk>
Date: Sun, 19 May 2019 08:37:33 +0200
Subject: [PATCH] If MNTP is configured to pick max 1 item, convert the value
 into IPublishedContent instead of IEnumerable<IPublishedContent>

---
 .../MultiNodeTreePickerValueConverter.cs       | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/src/Umbraco.Web/PropertyEditors/ValueConverters/MultiNodeTreePickerValueConverter.cs b/src/Umbraco.Web/PropertyEditors/ValueConverters/MultiNodeTreePickerValueConverter.cs
index a210aa62c6..4bb33fd2da 100644
--- a/src/Umbraco.Web/PropertyEditors/ValueConverters/MultiNodeTreePickerValueConverter.cs
+++ b/src/Umbraco.Web/PropertyEditors/ValueConverters/MultiNodeTreePickerValueConverter.cs
@@ -43,7 +43,9 @@ namespace Umbraco.Web.PropertyEditors.ValueConverters
             => PropertyCacheLevel.Snapshot;
 
         public override Type GetPropertyValueType(PublishedPropertyType propertyType)
-            => typeof (IEnumerable<IPublishedContent>);
+            => IsSingleNodePicker(propertyType)
+                ? typeof(IPublishedContent)
+                : typeof(IEnumerable<IPublishedContent>);
 
         public override object ConvertSourceToIntermediate(IPublishedElement owner, PublishedPropertyType propertyType, object source, bool preview)
         {
@@ -73,6 +75,7 @@ namespace Umbraco.Web.PropertyEditors.ValueConverters
                 if (propertyType.EditorAlias.Equals(Constants.PropertyEditors.Aliases.MultiNodeTreePicker))
                 {
                     var udis = (Udi[])source;
+                    var isSingleNodePicker = IsSingleNodePicker(propertyType);
 
                     if ((propertyType.Alias != null && PropertiesToExclude.InvariantContains(propertyType.Alias)) == false)
                     {
@@ -102,9 +105,17 @@ namespace Umbraco.Web.PropertyEditors.ValueConverters
                             if (multiNodeTreePickerItem != null && multiNodeTreePickerItem.ItemType != PublishedItemType.Element)
                             {
                                 multiNodeTreePicker.Add(multiNodeTreePickerItem);
+                                if (isSingleNodePicker)
+                                {
+                                    break;
+                                }
                             }
                         }
 
+                        if (isSingleNodePicker)
+                        {
+                            return multiNodeTreePicker.FirstOrDefault();
+                        }
                         return multiNodeTreePicker;
                     }
 
@@ -141,5 +152,10 @@ namespace Umbraco.Web.PropertyEditors.ValueConverters
             }
             return content;
         }
+
+        private static bool IsSingleNodePicker(PublishedPropertyType propertyType)
+        {
+            return propertyType.DataType.ConfigurationAs<MultiNodePickerConfiguration>().MaxNumber == 1;
+        }
     }
 }