azure - Querying DocumentDB for a list of propertiers using Linq's Select -

using azure's documentdb , .net api, have following method works great retrieving lists of entire documents:

   public async task<ienumerable<t>> getitemsasync<t>(expression<func<t, bool>> predicate)     {                     idocumentquery<t> query = _client.createdocumentquery<t>(             urifactory.createdocumentcollectionuri(_databaseid, _collection),             new feedoptions { maxitemcount = -1 })             .where(predicate)             .asdocumentquery();          list<t> results = new list<t>();         while (query.hasmoreresults)         {             var item = await query.executenextasync<t>();             results.addrange(item);         }          return results;     } 

now, don't want return entire document (especially considering documentdb ru pricing model), thought should able add .select projection so:

 public async task<list<tresult>> getitemsasync<t, tresult>(expression<func<t, bool>> predicate, expression<func<t, tresult>> select)         {             idocumentquery<tresult> query = _client.createdocumentquery<t>(                 urifactory.createdocumentcollectionuri(_databaseid, _collection),                 new feedoptions { maxitemcount = -1 })                 .where(predicate)                 .select(select)                 .asdocumentquery();              list<tresult> results = new list<tresult>();             while (query.hasmoreresults)             {                 var item = await query.executenextasync<tresult>();                 results.addrange(item);             }              return results;         } 

usage:

var rez = await _docs.getitemsasync<apolloassetdoc, guid?>(x => x.myval == 5, x => x.id); 

but second method return 0 results. i'm barking wrong tree.

any idea correct way return list of either dynamic objects queries more 1 property selected (eg "select d.id, d.myval items d d.doctype=0")or simple list single property selected (eg "select d.id items d d.doctype=0")?

i repro issue, if there no [jsonproperty(propertyname = "id")] id property in entity class. if not included, please have try use following code:

public class apolloassetdoc     {         [jsonproperty(propertyname = "id")]         public guid id { get; set; }         public string myval { get; set; }      } 

note: field case sensitive.