See the example below to see how a value can be added or changed programmatically. To update a value of a property editor you need the Content Service.
The example below demonstrates how to add values programmatically using a Razor view. However, this is used for illustrative purposes only and is not the recommended method for production environments.
@using Umbraco.Cms.Core.Services;
@inject IContentService Services;
@using Newtonsoft.Json
@{
// Get access to ContentService
var contentService = Services;
// Create a variable for the GUID of the page you want to update
var guid = Guid.Parse("32e60db4-1283-4caa-9645-f2153f9888ef");
// Get the page using the GUID you've defined
var content = contentService.GetById(guid); // ID of your page
// Set the value of the property with alias 'categories'.
content.SetValue("categories", JsonConvert.SerializeObject(new[] { "News" }));
// Save the change
contentService.Save(content);
}
Although the use of a GUID is preferable, you can also use the numeric ID to get the page:
@{
// Get the page using it's id
var content = contentService.GetById(1234);
}
If Modelsbuilder is enabled you can get the alias of the desired property without using a magic string:
@using Umbraco.Cms.Core.PublishedCache;
@inject IPublishedSnapshotAccessor _publishedSnapshotAccessor;
@{
// Set the value of the property with alias 'categories'
content.SetValue(Home.GetModelPropertyType(_publishedSnapshotAccessor, x => x.Categories).Alias, JsonConvert.SerializeObject(new[] { "News" }));
}