OData pagination with WebApi ( $inlinecount )

Question

I am using OData to paginate a long list of items returned from a web api call. I can filter the data via the url with the start and end index.

The question I have is, how do I know the total number of items? So I can display Page 1 of 3 (20 items) on my mobile device which calls the web api.

Answer 1

Here is a link to a working version, it have been implemented as a QueryableAttribute. http://aspnetwebstack.codeplex.com/SourceControl/changeset/view/88372a0b4ab9#src%2fMicrosoft.Web.Http.Data%2fQueryFilterAttribute.cs

edit: Use this link for a detailed explaination -> http://www.strathweb.com/2012/08/supporting-odata-inlinecount-with-the-new-web-api-odata-preview-package/

Answer 2

You can use $inlinecount=allpages in the query to get the count of all the entities in the results without the top and skip. For example:

http://services.odata.org/OData/OData.svc/Products?$top=1&skip=1&$inlinecount=allpages

Returns a single product but also inline count of 9 (since there are 9 products in the entity set).

Answer 3

Try this approach: http://www.strathweb.com/2012/08/supporting-odata-inlinecount-with-the-new-web-api-odata-preview-package/

It uses the latest Web API OData package.

Until the finalized Web API OData package is shipped (sometime this fall, should be around in November), when the $inlinecount is supported out of the box, this solution is likely the best bet.

Answer 4

I had the exact issue last week. Check out Extending your ASP.NET Web API responses with useful metadata

I used this post and sample code to get a paging grid up and running using OData. As detailed in the sample I created a delegating handler to capture the HttpResponseMessage and wrap it in custom metadata that includes an item count. A custom attribute, CustomQueryableAttribute, is also created that inherits the default QueryableAttribute.

It may sound a little complex here but is actually pretty simple to implement. I had something up and running in about 30 minutes.

Hopefully future versions of the Web API have more complete OData support.

EDIT: Odata support will NOT be shipping with the Web API. The queryable attribute is being removed for the RTM release. More complete OData support will be available sometime after the initial relase via a separate Nuget package.