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 1/2] 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;
+        }
     }
 }

From f07fcac13dd91e34a32dc99430eb5b33db68c6e4 Mon Sep 17 00:00:00 2001
From: Kenn Jacobsen <post@kennjacobsen.dk>
Date: Sun, 19 May 2019 08:38:03 +0200
Subject: [PATCH 2/2] If MNTP is configured to pick max 1 item, don't allow
 multiselect in the content picker dialog

---
 .../contentpicker/contentpicker.controller.js                | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/Umbraco.Web.UI.Client/src/views/propertyeditors/contentpicker/contentpicker.controller.js b/src/Umbraco.Web.UI.Client/src/views/propertyeditors/contentpicker/contentpicker.controller.js
index 33cf24962f..4d695c97b5 100644
--- a/src/Umbraco.Web.UI.Client/src/views/propertyeditors/contentpicker/contentpicker.controller.js
+++ b/src/Umbraco.Web.UI.Client/src/views/propertyeditors/contentpicker/contentpicker.controller.js
@@ -157,6 +157,11 @@ function contentPickerController($scope, entityResource, editorState, iconHelper
     // pre-value config on to the dialog options
     angular.extend(dialogOptions, $scope.model.config);
 
+    // if we can't pick more than one item, explicitly disable multiPicker in the dialog options
+    if ($scope.model.config.maxNumber && parseInt($scope.model.config.maxNumber) === 1) {
+        dialogOptions.multiPicker = false;
+    }
+
     // add the current filter (if any) as title for the filtered out nodes
     if ($scope.model.config.filter) {
         localizationService.localize("contentPicker_allowedItemTypes", [$scope.model.config.filter]).then(function (data) {