Elasticsearch search query to retrieve all records NEST

Here is how I solved my problem. Hope this helps. (References https://www.elastic.co/guide/en/elasticsearch/client/net-api/1.x/scroll.html , https://www.elastic.co/guide/en/elasticsearch/reference/current/search-request-scroll.html#scroll-search-context)

List<string> indexedList = new List<string>();
var scanResults = client.Search<ClassName>(s => s
                .From(0)
                .Size(2000)
                .MatchAll()
                .Fields(f=>f.Field(fi=>fi.propertyName)) //I used field to get only the value I needed rather than getting the whole document
                .SearchType(Elasticsearch.Net.SearchType.Scan)
                .Scroll("5m")
            );

        var results = client.Scroll<ClassName>("10m", scanResults.ScrollId);
        while (results.Documents.Any())
        {
            foreach(var doc in results.Fields)
            {
                indexedList.Add(doc.Value<string>("propertyName"));
            }

            results = client.Scroll<ClassName>("10m", results.ScrollId);
        }

EDIT

var response = client.Search<Document>(s => s
                         .From(fromNum)
                         .Size(PageSize)
                         .Query(q => q ....