Complex objects

4 min

Use filters to narrow down search results, or use them for database-like queries.

The REST API and .NET client API support varying degrees of filtering on complex objects of different types. You can divide supported complex objects into the following types:

Collections of native objects such as IEnumerable<int>.

Complex objects that have properties of native objects and complex objects, for example, an Author class.

Collections of complex objects, such as IEnumerable<Author>.

Collection of native objects

The documentation covers the first type for each native type. For instance, if you want to know how to filter on a property of type IEnumerable<string>, see Strings.

Complex objects with properties of native objects

The second type, complex objects, such as a property of type Author is straightforward. You can filter on its native properties as if they were a part of the type you are searching for. For instance, to find blog posts authored by Winston Churchill, you could use the following code.

Example:

var searchQuery = client.Search<BlogPost>()
  .Filter(x => x.Author.Name.Match("Winston Churchill"));

One might wonder what happens if the Author property is null. It does not throw an exception, contrary to LINQ. The filter does not match.

Complex object collections

The final type of complex objects that you can filter is a collection of complex objects, such as IEnumerable<Author>. The .NET client API has a filter method named MatchContained, which you can use to filter on properties of native types in objects in collections. Imagine that the BlogPost class no longer has an Author property but instead an Authors property of type IEnumerable<Author>. Next, use the MatchContained method to find blog posts whose Author property contains an Author with a specific name.

Example:

var searchQuery = client.Search<BlogPost>()
  .Filter(x => x.Authors.MatchContained(a => a.Name, "Winston Churchill"));

Not The MatchContained syntax is a bit different from other filtering methods. The first argument is an expression identifying the property that we want to filter on. The second argument is the value.

Also, while the MatchContained method lets you filter on a single field in an object in a list, you cannot use it to express multiple conditions on the same object in the list. Use it to find blog posts with an author named Winston Churchill and an author with a specific email address. You cannot use it to find blog posts with an author's exact name and email address.