Use a generic tree directive

Feather's sfTree directive enables you to display items hierarchically and provides you with the functionality to retrieve the selected item. You can use the directive to display hierarchical tree in the frontend, as well as in the backend. For example, on a page, as well as in a widget designer. For more information, see Use content selectors outside of a widget designer's view.

The sfTree directive exposes the following attributes:

Attribute	Description
sf-request-children	Accepts a callback function that must provide a promise with the array of items that are going to be displayed. The callback must return the root items or the child items of the currently selected node. The callback function is invoked during the initial load of the sfTree directive. The callback function is also invoked for each subsequent expansion if the child nodes of the selected item have not been retrieved yet.
sf-model	Accepts a scope variable that references the identifier field of the selected item. If there is no selected item, the value of this variable is null.
sf-identifier	Specifies which property value is to be exposed in the sf-model collection. If you do not specify this attribute, the sfTree directive exposes the item itself in the sf-model collection.
sf-expand-on-select	Specifies whether the tree should be expanded when an item is selected.
sf-deselectable	Specifies whether the tree allows selected items to be deselected when they are clicked again. If an item is deselected, the value of the sf-model is set to null.
sf-template-url	Allows you to override the template of the tree.
sf-template-assembly	Specifies the assembly where the template of the tree is located.
sf-item-template-url	Allows you to override the item template of the tree.
sf-item-template-assembly	Specifies the assembly where the item template of the tree is located.
sf-has-children-field	Accepts the name of the scope variable that determines whether a node has children. If this attribute value is not explicitly specified, the sfTree assumes that a node has children. When requesting the children of a node that has no children, an empty array is received as a response.

The sfTree is a directive with an isolated scope that is defined in a module with the same name: sfTree.

Add the generic tree directive

The following example demonstrates how to add a generic tree directive in a widget designer's view.

To enable AngularJs to link the sfTree directive in your custom designer view, you must load the script of the directive and add a dependency to the module:

1. In your DesignerView.YourView.json file, add a scripts array. As a result, the file content should be similar to the following:

   {
      "priority": 1,
      "scripts": [
        "client-components/collections/sf-tree.js"
        ]
   }

2. In your designerview-yourview.js file, right before the definition of your custom view controller, place the following code snippet:

   var designerModule = angular.module('designer');
   angular.module('designer').requires.push('sfTree');

3. In your DesignerView.YourView.cshtml file, place the following tag where you want to render the sfTree directive:

  <sf-tree 
      sf-model="selectedItemId" 
      sf-request-children="requestChildrenCallback(parent)" 
      sf-identifier="Key" 
      sf-has-children-field="IsParent" 
      sf-expand-on-select/>

4. In your designer's controller, add the following code:

designerModule.controller('SettingsCtrl', ['$scope', '$q', function ($scope, $q) { $scope.requestChildrenCallback = function (parentObj) { parentObj = parentObj || {}; var parent = parentObj.IsParent; var result = $q.defer();

		if (!parent) {
			result.resolve([{ Key: '1', Title: 'Title Root 1', IsParent: true },
							{ Key: '2', Title: 'Root 2', IsParent: false }]);
		}
		else {
			result.resolve([{ Key: parentObj.Key + '#1', Title: '1st child of ' + parentObj.Key, IsParent: true },
							{ Key: parentObj.Key + '#2', Title: '2nd child of ' + parentObj.Key, IsParent: false }]);
		}

		return result.promise;
	};

}]); ``` The code above is invoked during the initial load of the sfTree directive and two root elements are added to the tree. If you select an item which is a parent, the tree expands and invokes the function. As a result, two more elements are added under the currently selected node. If the sf-has-children-field attribute is present, its scope variable is evaluated. If the attribute is not present, all elements of the tree visually appear as if they have children. If you try to expand such an element, the response is an empty array and the item no longer appears as a parent.

Subscribe to selection event

To provide notification when an item is selected the sfTree directive emits a custom selection event. To subscribe to the selection event, use the following code in your desinger's controller:

$scope.$on('sf-tree-item-selected', function (event, item) { });