Fixes: U4-3501 Error when selecting multiple items with the media picker in v7 - ensures the standard media picker cannot multi-select, hides the add button when multi select is disabled and there's a value.

src/Umbraco.Web.UI.Client/src/views/propertyeditors/mediapicker/mediapicker.controller.js

@@ -3,6 +3,8 @@
 angular.module('umbraco').controller("Umbraco.PropertyEditors.MediaPickerController",
     function($rootScope, $scope, dialogService, mediaResource, imageHelper, $log) {
 
+        //check the pre-values for multi-picker
+        var multiPicker = $scope.model.config.multiPicker !== undefined ? $scope.model.config.multiPicker : true;
 
         function setupViewModel() {
             $scope.images = [];
@@ -33,9 +35,14 @@ angular.module('umbraco').controller("Umbraco.PropertyEditors.MediaPickerControl
 
         $scope.add = function() {
             dialogService.mediaPicker({
-                multiPicker: true,
+                multiPicker: multiPicker,
                 callback: function(data) {
                     
+                    //it's only a single selector, so make it into an array
+                    if (!multiPicker) {
+                        data = [data];
+                    }
+                    
                     _.each(data, function(media, i) {
                         var img = {};
                         img.id = media.id;
@@ -67,6 +74,15 @@ angular.module('umbraco').controller("Umbraco.PropertyEditors.MediaPickerControl
             $scope.model.value = $scope.ids.join();
         };
 
+        $scope.showAdd = function () {
+            if (!multiPicker) {
+                if ($scope.model.value && $scope.model.value !== "") {
+                    return false;
+                }
+            }
+            return true;
+        };
+
         //here we declare a special method which will be called whenever the value has changed from the server
         //this is instead of doing a watch on the model.value = faster
         $scope.model.onValueChanged = function (newVal, oldVal) {

src/Umbraco.Web.UI.Client/src/views/propertyeditors/mediapicker/mediapicker.html

@@ -8,7 +8,7 @@
 		</li>
 	</ul>
 
-	<ul class="thumbnails umb-thumbnails">
+	<ul class="thumbnails umb-thumbnails" ng-if="showAdd()">
 		<li class="umb-thumbnail thumbnail">
 			<a href="#" class="add-link" ng-click="add()" prevent-default>
 				<i class="icon icon-add large"></i> 

src/Umbraco.Web/PropertyEditors/MediaPickerPropertyEditor.cs

@@ -12,12 +12,28 @@ namespace Umbraco.Web.PropertyEditors
     [PropertyEditor(Constants.PropertyEditors.MediaPickerAlias, "Media Picker", "INT", "mediapicker")]
     public class MediaPickerPropertyEditor : PropertyEditor
     {
+        public MediaPickerPropertyEditor()
+        {
+            _defaultPreValues = new Dictionary<string, object>
+                {
+                    {"multiPicker", false}
+                };
+        }
+
+        private IDictionary<string, object> _defaultPreValues;
+
         protected override PropertyValueEditor CreateValueEditor()
         {
             //TODO: Need to add some validation to the ValueEditor to ensure that any media chosen actually exists!
 
             return base.CreateValueEditor();
+            
         }
 
+        public override IDictionary<string, object> DefaultPreValues
+        {
+            get { return _defaultPreValues; }
+            set { _defaultPreValues = value; }
+        }
     }
 }