public decimal Sum(string predicate, IEnumerable conditionParameters)
{
Dictionary <string, object> parameters = new Dictionary <string, object>();
int i = 1;
foreach (var parameter in conditionParameters)
{
object p = parameter;
// it is need for calculating linq
IEnumerable enumerable = parameter as IEnumerable;
if (enumerable != null && !(parameter is string))
{
ArrayList list = new ArrayList();
foreach (var item in enumerable)
{
list.Add(item);
}
p = list;
}
parameters.Add(string.Format("p{0}", i), p);
i++;
}
ExpressionFactory factory = new ExpressionFactory(_context, typeof(T), parameters);
Func <object, decimal> func = factory.BuildArithmeticExpression(predicate);
decimal result = _collection.Sum(val => func(val));
return(result);
}