ElasticLINQ is a free C# library for searching Elasticsearch using LINQ syntax in .NET, e.g.
var db = new ElasticContext(new ElasticConnection(new Uri("http://myserver:9200"))); var p = db.Query<People>().Where(p => p.Tags.Contains("tech") && p.State == "WA");
ElasticLINQ supports .NET 4.5 & PCL with Elasticsearch 0.9.0 through Elasticsearch 1.7.
Elasticsearch 2.0 is not fully tested. Many queries should work although GroupBy will fail because it uses the older facets system from Elasticsearch 1.x.