Sort on multiple fields doesn't work

[SLavrynenko]

"version" : {
"number" : "2.4.4",
"build_hash" : "fcbb46dfd45562a9cf00c604b30849a6dec6b017",
"build_timestamp" : "2017-01-03T11:33:16Z",
"build_snapshot" : false,
"lucene_version" : "5.5.2"
},

NEST version 2.4.6

I've the following code:

response = client.Search(
s => s.Query(
q => GetQueryContainer(q))
.Index(Settings.IndexName)
.Source(sfd => SourceSelector(sfd))
.From(fromRow)
.Size(pageSize)
.Sort(s1 => s1.Field("Firstname", SortOrder.Descending))
.Sort(s1 => s1.Field("Lastname", SortOrder.Descending))
);

and as I see in the logs I have sort on the field that is used in the last Sort method. If I add the new Sort method in a chain I will get sorting on that field and not on all of them:

Request that code above is provided:
{"from":0,"size":20,"sort":[{"Lastname":{"order":"desc"}}],"_source":{"include":["Firstname","Lastname"],"exclude":[]},"query":{...}}

At debugger in MS Visual Studio I see that internal Sort collection has only 1 item after each call of Sort method. So it doesnt add anything to a collection - just rewrite the only 1 item every time.

[SLavrynenko]

From the source code I see following:

///<summary>
		///A comma-separated list of fields to return as the field data representation of a field for each hit
		///</summary>
		public SearchDescriptor<T> Sort(Func<SortDescriptor<T>, IPromise<IList<ISort>>> selector) => Assign(a => a.Sort = selector?.Invoke(new SortDescriptor<T>())?.Value);

so, a.Sort = selector?.Invoke(..) and not a.Sort.Add(...) - is it ok?

[russcam]

It's correct @SLavrynenko; To sort on multiple fields in NEST 2.x+ is

var searchResponse = client.Search<object>(s => s
    .Query(q => q
        .MatchAll()
    )
    .Sort(s1 => s1
        .Field("Firstname", Nest.SortOrder.Descending)
        .Field("Lastname", Nest.SortOrder.Descending)
    )
);

which produces

{
  "sort": [
    {
      "Firstname": {
        "order": "desc"
      }
    },
    {
      "Lastname": {
        "order": "desc"
      }
    }
  ],
  "query": {
    "match_all": {}
  }
}

All sort expressions should be inside the one .Sort(Func<SortDescriptor<T>, IPromise<IList<ISort>>> selector); the NEST structure was changed in 2.x to better represent the structure in the Elasticsearch query DSL.

[whittssg]

@russcam Is there a way to provide a list to .Sort? a bit like you can for Filter? I have checked everywhere and I cant seem to find anyway to do it apart from if i use Object Initalizer.

I thought something like this would work:

var testSort = new List<ISort>();
foreach (var option in mySortList)
{
testSort.Add(new FieldSort { Field = option.Key, Order = option.SortOrder == "ASC" ? SortOrder.Ascending : SortOrder.Descending });
} 
.Sort(testSort)

Thanks

EDIT Figured it out (maybe there should be an option to just add a list of ISort to .Sort() ?

 Func<SortDescriptor<dynamic>, IPromise<IList<ISort>>> sortList = st =>
            {
                if (queryBuilder.Sort != null)
                {
                    foreach (var option in queryBuilder.Sort)
                    {    
                        if (option.SortOrder == "ASC")
                        {
                            st.Ascending(option.Key);
                        }
                        else
                        {
                            st.Descending(option.Key);
                        }
                    }
                }
                else
                {
                    st.Ascending(SortSpecialField.Score);
                }
                return st;
            };