Sum of expression lamba on List

Hi

I was trying to make an evaluation, a Sum on a List, but I’m getting an error: CodingSeb.ExpressionEvaluator.ExpressionEvaluatorSyntaxErrorException: ‘Function [Sum] unknown in expression : [Sum(x => x.Nombre == “uno” ? (x.Valor ?? 0m) : 0m)]’

What am I doing wrong? or it is not supported?

var Lista = new List<Test>() { new Test { Nombre = "uno", Valor = 1.11m }, new Test { Nombre = "uno", Valor = 2.22m }, new Test { Nombre = "uno", Valor = null }, new Test { Nombre = "dos", Valor = 3.33m } };
string script = "Sum(x => x.Nombre == \"uno\" ? (x.Valor ?? 0m) : 0m)";

ExpressionEvaluator Eval = new ExpressionEvaluator()
{
      StaticTypesForExtensionsMethods = new List<Type> { typeof(Enumerable) },
      Namespaces = new List<string>() { "System", "System.Linq"},
      OptionVariableAssignationActive = false, 
      OptionPropertyOrFieldSetActive = false, 
      CacheTypesResolutions = true
};

Eval.Context = Lista;

var result = Eval.Evaluate(script);

// ***********************************************************************
public class Test
{
     public string Nombre { get; set; }
     public decimal? Valor { get; set; }
}

[TheoVC]

Hi

Yes I tested and it’s working perfectly fine. it’s the perfect solution for indexing… and for calling context methods…

var Lista = new List<Person>() { new Person { Name = "uno", Value = 1.1m }, new Person { Name = "dos", Value = 2.2m } };

var Eval = new ExpressionEvaluator();
Eval.Context = Lista;
var temp = Eval.Evaluate("10.5m + this.Sum(x => x.Value) + this[0].Value");

Actually this code is in production already… 😃

[codingseb]

new version 1.4.30.0 introduce the this keyword to manage extention methods and indexing on Context. Thanks @TheoVC.