I came across something cool today! When a CheckList, MultiList, TreeList, or etc. field are on your template, they eventually call into the Sitecore.Web.UI.HtmlControls.Data.LookupSources.GetItems() class and method. This calls the getLookupSourceItems pipline. This pipeline contains the following processor:

[code language=”xml”]
<getLookupSourceItems>
<processor type="Sitecore.Buckets.FieldTypes.CustomDataSource, Sitecore.Buckets" patch:source="Sitecore.Buckets.config"/>
</getLookupSourceItems>
[/code]

If we take a look at Sitecore.Buckets.FieldTypes.CustomDataSource in Sitecore.Buckets.dll, we can see that this class will allow us to prefix our source field with “code:” and then add a type and assembly that implements Sitecore.Buckets.FieldTypes.IDataSource to return a list of items.

Lets take a look at an example. I’ve created a class that implements IDataSource:

[code language=”csharp”]
using Sitecore.Buckets.FieldTypes;
using Sitecore.Data.Items;

namespace Hi.Sc.Buckets
{
public class CustomDataSource : IDataSource
{
public Item[] ListQuery(Item item)
{
string homePath = "/sitecore/content/home";
Item homeItem = Sitecore.Context.ContentDatabase.GetItem(homePath);
if (homeItem != null)
{
return homeItem.GetChildren().ToArray();
}
return new Item[0];
}
}
}
[/code]

You’ll need to include Sitecore.Buckets.dll as a reference in your project. Next add a field to an existing template:

I’ve added the following line to my source field of my MultiList where Hi.Sc.Buckets.CustomDataSource is my class that implements Sitecore.Buckets.FieldTypes.IDataSource and Hi.Sc is the name of my dll:

[code language=”csharp”]
code:Hi.Sc.Buckets.CustomDataSource, Hi.Sc
[/code]

When I take a look at my MultiList, you can see it is pulling the children of the home item:

This can be expanded upon to create some really cool lists of items and I think we can all agree that it is easier to write C# code than Sitecore Query.