C# Driver- LINQ - Aggragate - Contains in Int[] -

mongo driver version: 2.2.4.26

i have following query performs aggregations. if remove contains predicate clause, query executes successfully.

i reduce , perform aggregation on server before realizing data client memory. issue encountering when use contains in clause, following exception:

$project or $group not support sum({document}{forecastquantity}).

i prefer stay in linq implementation vs. native if possible:

public class forecast {     public int markdowngroupid { get; set; }     public list<forecastdata> forecastarray { get; set; } ... }  public class forecastdata {     public int markdownnumber { get; set; }     public double forecastquantity { get; set; } ... }  public class flat {     public int markdowngroupid { get; set; }     public int markdownnumber { get; set; }     public double salesquantity { get; set; }  ... }  public class flatprojection {     public int markdowngroupid { get; set; }     public int markdownnumber { get; set; }     public double salesquantity { get; set; }  ... }  int[] groupids = new int[]{ 1,2,3 }; var forecastproductday = _mdb.getcollection<forecast>(collectionname);          var forecastproductprojections = forecastproductday             .asqueryable()             .where(x => groupids.contains(x.markdowngroupid))             .selectmany(x => x.forecastarray, (x, fa) => new flat                     {                 markdowngroupid = x.markdowngroupid,                 markdownnumber = fa.markdownnumber,                 forecastquantity = fa.forecastquantity,                 ...             })             .groupby(key => new {key.markdowngroupid, key.markdownnumber})             .select(g => new flatprojection             {                 markdowngroupid = g.key.markdowngroupid,                 markdownnumber = g.key.markdownnumber,                 salesquantity = g.sum(y => y.forecastquantity),                 ...             })             .orderby(x => x.markdowngroupid)             .thenby(x => x.markdownnumber)             .tolist(); 

since driver not contains() or any(). had build expression dynamically using predicatebuilder.

public static class predicatebuilder {     public static expression<func<t, bool>> true<t>() { return f => true; }     public static expression<func<t, bool>> false<t>() { return f => false; }      public static expression<func<t, bool>> or<t>(this expression<func<t, bool>> expr1,                                                         expression<func<t, bool>> expr2)     {         var invokedexpr = expression.invoke(expr2, expr1.parameters.cast<expression>());         return expression.lambda<func<t, bool>>               (expression.orelse(expr1.body, invokedexpr), expr1.parameters);     }      public static expression<func<t, bool>> and<t>(this expression<func<t, bool>> expr1,                                                          expression<func<t, bool>> expr2)     {         var invokedexpr = expression.invoke(expr2, expr1.parameters.cast<expression>());         return expression.lambda<func<t, bool>>               (expression.andalso(expr1.body, invokedexpr), expr1.parameters);     } } 

list ints = new list() {1,2,3};

        var predicate = predicatebuilder.false<forecast>();         foreach (var in ints)         {             predicate = predicate.or(x => x.markdowngroupid == i);         } 

var forecastproductday = _mdb.getcollection(collectionname);

    var forecastproductprojections = forecastproductday         .asqueryable()         .where(predicate.compile())         .selectmany(x => x.forecastarray, (x, fa) => new flat                 {             markdowngroupid = x.markdowngroupid,             markdownnumber = fa.markdownnumber,             forecastquantity = fa.forecastquantity,             ...         })         .groupby(key => new {key.markdowngroupid, key.markdownnumber})         .select(g => new flatprojection         {             markdowngroupid = g.key.markdowngroupid,             markdownnumber = g.key.markdownnumber,             salesquantity = g.sum(y => y.forecastquantity),             ...         })         .orderby(x => x.markdowngroupid)         .thenby(x => x.markdownnumber)         .tolist();