Sitecore: extending field datasource queries with tokens

It is quite common situation when you need to create data source query for a field in a template that is quite complex: e.g you would like to use current item property as a part of a query or you have dependency on some other item in a content tree.

In case of list fields you could use GetLookupSourceItems pipelines to modify query according to your requirements.

	namespace IExamples.Sc.Pipelines.GetLookupSourceItems
	{
	using System.Linq;
	using Sitecore.Data;
	using Sitecore.Data.Fields;
	using Sitecore.Data.Items;
	using Sitecore.Diagnostics;
	using Sitecore.Pipelines.GetLookupSourceItems;
	public class DataSourceTokens
	{
	public void Process(GetLookupSourceItemsArgs args)
	{
	Assert.ArgumentNotNull(args, "args");
	// Custom code to get value of dependency
	var dependency = "some value";
	// set default values for tokens
	var token = dependency ?? "."
	// replace tokens in datasource of the field
	args.Source = args.Source
	.Replace("{{token}}", token);
	}
	}
	}

view raw DataSourceTokens.cs hosted with ❤ by GitHub

As usual you will need to register this pipeline in sitecore patch file and put it in <web root>/app_config/include

Finally, to use it need to use defined token in a field query, when you defining your template.

Simple, but give you a lot of flexibility.