Programmatically set Sitecore.Context

Question

I'm trying to build a custom admin utility page which will add renderings to a page. The action happens in an Ajax call and so the Sitecore.Context is unavailable. I do have the pageItem though.

LayoutField layoutField = new LayoutField(pageItem.Fields[FieldIDs.LayoutField]);
LayoutDefinition layoutDefinition = LayoutDefinition.Parse(layoutField.Value);
var contextDb = Sitecore.Context.Database;
DeviceDefinition deviceDefinition = layoutDefinition.GetDevice(Sitecore.Context.Device.ID.ToString());

In the above code, contextDb is null & deviceDefition throws an error because Sitecore.Context.Device is null.

Is there a way to programmatically set the Sitecore.Context or get it from the pageItem.

Using Sitecore 9.3

Answer 1

If you have the pageItem which is an instance of Sitecore.Data.Items.Item class, you can wrap your code into a DatabaseSwitcher and DeviceSwitcher

        using (new DatabaseSwitcher(pageItem.Database))
        {
            using (new DeviceSwitcher(pageItem.Database.Resources.Devices.GetAll().FirstOrDefault(t=>t.Name.Equals("default",System.StringComparison.OrdinalIgnoreCase)))))
            {
                // Add your code block here
            }
        }

Answer 2

To resolve device item, you can use this:

var deviceItem = Sitecore.Data.Items.DeviceItem.ResolveDevice(pageItem.Database);

Then you can use one of the approaches below:

1. Sitecore.Context.Device = deviceItem; // doesn't validate deviceItem
2. Sitecore.Context.Data.Device = deviceItem; // validates deviceItem
3. using(new DeviceSwitcher(deviceItem)) { /*your code here*/ }

You also can use the switchers below (if needed) to switch Context.Database and Context.Item if they are null:

1. using (new DatabaseSwitcher(pageItem.Database)) {}
2. using (new ContextItemSwitcher(pageItem)) {}

Answer 3

Sitecore can do all this for you as well without the need to write any custom code when you pass the Guid of the item in sc_itemid query string in your Ajax call. I just tested and this will get Sitecore.Context.Device populated with default device.

Note that you might need more querystrings if you are after additional info. For example Sitecore cannot determine the context site unless you also specify sc_site