Lucene Boost with LINQ in Sitecore 7 ContentSearch

Finally figured out how to boost certain fields using Sitecore 7’s ContentSearch LINQ provider. Boosting provides relevance enhancements when a search term is found within a field. For example, a search term found in a documents title or keywords field is probably way more relevant than if its found in the body.

You may have stumbled across the Boost extension method but couldn’t get it to work.

The issue is that the Boost extension method does not work with the == operator: you have to use a method like .Equals or .Matches. (I think I’ll throw up another post with the other provided LINQ operators).

So if you have a document type like BlogSearchResultItem:

BlogSearchResultItem.cs
using Sitecore.ContentSearch;
using Sitecore.ContentSearch.SearchTypes;

public class BlogSearchResultItem : SearchResultItem
{
    [IndexField("title")]
    public string Title { get; set; }

    [IndexField("keywords")]
    public string Keywords { get; set; }

    [IndexField("body")]
    public string Body { get; set; }
}

You can boost the search term using Boost:

Search.cs
public SearchResults<BlogSearchResultItem> Search(string term)
{
    using (var context = ContentSearchManager.GetIndex("blog_posts").CreateSearchContext())
    {
        var query = context.GetQueryable<BlogSearchResultItem>();
        return query.Where(b =>
            b.Title.Equals("test").Boost(2.0f) ||
            b.Keywords.Equals("test").Boost(1.5f) ||
            b.Body == "test").GetResults();
    }
}

This should yield the following Lucene query:

Search.log.txt
title:test^2.0 keywords:test^1.5 body:test