private static void ApplyPredicate <TEntity, TForeign>(AggregateQueryable <TEntity> aggregateQueryable, Expression predicate, string asFieldName)
{
if (predicate == null)
{
return;
}
var foreignType = typeof(TForeign);
var isEnumerable = typeof(TForeign).IsEnumerable();
if (isEnumerable)
{
foreignType = foreignType.GetElementTypeOf();
}
//lamb = Expression.Lambda(methodCall.Arguments[0], Expression.Parameter(typeof(TEntity), "p"));
var filterDefinitionBuilder = new FilterDefinitionBuilder <TEntity>();
var param1Type = typeof(FieldDefinition <TEntity>);
var param2Type = typeof(FilterDefinition <>).MakeGenericType(foreignType);
var method = filterDefinitionBuilder.GetType()
.GetGenericMethod(nameof(filterDefinitionBuilder.ElemMatch), BindingFlags.Public | BindingFlags.Instance,
new[] { foreignType }, new[] { param1Type, param2Type }, typeof(FilterDefinition <TEntity>));
var expressionFilterDefinition = Activator.CreateInstance(typeof(ExpressionFilterDefinition <>).MakeGenericType(foreignType), predicate);
var asField = new StringFieldDefinition <TEntity>(asFieldName);
var elmMatch = (FilterDefinition <TEntity>)method.Invoke(filterDefinitionBuilder, new object[] { asField, expressionFilterDefinition });
//Filter ($match) elements of TForeign using predicate
aggregateQueryable.AggregateFluent = aggregateQueryable.AggregateFluent.Match(elmMatch);
}
