List Fields

The built-in ContentList type (and all the inherited ones like DocumentLibrary or TaskList) has a few legacy features that are now under rethinking and re-development (e.g. notifications, workflows). One of them is the possibility to add so called expando fields directly to individual lists without editing the type definition xmls and make a field available through the whole repository. Although this feature is not pushed to the forefront, let's see some examples of what we can do with it through OData.

Browsing list fields

List fields have a # prefix, so their names look like #MyField. Except for this, they are not different from the other fields in terms of OData, they can be selected, expanded, used in queries or in paging and ordering.

Lets see a JSON response of a requested list item with an expando field:

{
  "d": {
    ...
    "DisplayName": "Kickoff meeting",
    "Location": "Meeting room 2.",
    "StartDate": "2019-05-10T00:00:00Z",
    "EndDate": "2019-05-12T00:00:00Z",
    "#EventType": "meeting"
    ...
}

Following example shows how to use expando fields in an OData request as selected field:

https://dev.demo.sensenet.com/OData.svc/Root/Content('IT')?$select=#CustomField

List expando fields defined on a specified list

sensenet lets you get the list of the custom fields added to an individual custom list requesting its metadata. Following request returns the Service Metadata Document of the specified instance that exposes the data model of the service in XML or JSON format:

https://dev.demo.sensenet.com/OData.svc/Root/Content/IT/Document_Library/$metadata

Add a new list field

The following example demonstrates how can you add a new metadata field to a content list, along with setting configuration values of the field (e.g. Compulsory or MinValue).:

url: "/OData.svc/Root/Content/IT('Document_Library')"
type: 'POST',
data: "models=[" + JSON.stringify({
  '__ContentType':'IntegerFieldSetting' ,
  Name: 'MyField1',
  'DisplayName': 'My Field 1',
  'Compulsory': true,
  'MinValue': 10
}) + "]",

Edit expando fields

sensenet represents custom list fields as virtual contents that can be managed in a similar way as regular content items.

You may edit the configuration values of a field in two different ways: treating the field as a virtual child of the content list (see the first two example below), or using a dedicated action, EditField, as in the third example:

url: "/OData.svc/Root/Content/IT/Document_Library('MyField1')",
type: 'PATCH',
data: "models=[" + JSON.stringify({
  'MinValue': 5,
  'MaxValue': 20 })
+ "]",

url: "/OData.svc/Content/IT/Document_Library('MyField1')",
type: 'PUT',
data: "models=[" + JSON.stringify({
  'MinValue': 5,
  'DisplayName': 'My field 1' })
+ "]",

url: "/OData.svc/Content/IT('Document_Library')/EditField",
type: 'POST',
data: "models=[" + JSON.stringify({
  Name: 'MyField1',
  'MinValue': 3,
  'MaxValue': 19 })
+ "]",

Remove a list field

You can delete a custom field in two different ways: treating the field as a virtual child of the content list (see the first example below), or using the DeleteField action, as in the second example:

url: "/OData.svc/Root/Content/IT/Document_Library('MyField1')",
type: 'DELETE',

url: "/OData.svc/Root/Content/IT('Document_Library')/DeleteField",
type: 'POST',
data: "models=[" + JSON.stringify({ name: 'MyField1' }) + "]",