Example of an Umbraco Backoffice controller used to do a bulk upgrade of certain content items

BulkController.cs

using System.Net;
using System.Net.Http;
using Umbraco.Web.WebApi;

namespace Example.Controllers
{
    /// <summary>
    /// Protectec Backoffice controller - Users must be logged in to call this
    /// Url: /umbraco/backoffice/api/bulk/PostPerformBulkUpdate
    /// </summary>
    public class BulkController : UmbracoAuthorizedApiController
    {
        //Add a model to pass in details like ContentType alias, PropertyType alias
        //and value to update
        public HttpResponseMessage PostPerformBulkUpdate()
        {
            //Find a ContentType with a specific alias
            var contentType = this.Services.ContentTypeService.GetContentType("myAlias");

            //Here we get all content items based on the above ContentType
            var contentService = this.Services.ContentService;
            var contentOfType = contentService.GetContentOfContentType(contentType.Id);
            //If you know the Ids of the content items 
            //var contentItems = contentService.GetByIds(new List<int> {1241, 1242, 1243});

            //Iterate the content items based on the "myAlias" ContentType
            foreach (var content in contentOfType)
            {
                //Update the value of a specific property 
                //(a check could have been done before this to ensure that the property exists and previous value was "X")
                content.Properties["myPropertyAlias"].Value = "a different value then before";

                //Save and publish the updated content item
                var status = contentService.SaveAndPublishWithStatus(content);
            }

            return Request.CreateResponse(HttpStatusCode.OK);
        }
    }
}