Currying Expressions in C#

Question

I am trying to build up an expression tree that I can feed into Linq2SQL so that it will generate a nice clean query. My purpose is to build a filter that takes an arbitrary

Answer 1

this example might help you. I guess the best is to build the expression without lambdas:

public class Entity
{
    public Entity(string someField)
    {
        SomeField = someField;
    }

    public string SomeField { get; set;  }
}

class Program
{
    static void Main(string[] args)
    {
        var entities = new[] {new Entity("fooBar"), new Entity("barBaz"), new Entity("baz"), new Entity("foo")};
        entities.Where(BuildExpression("ar","az").Compile())
                .ToList()
                .ForEach(e => Console.WriteLine(e.SomeField));
        Console.ReadLine();
    }

    public static Expression> BuildExpression(params string[] words)
    {
        var parameter = Expression.Parameter(typeof (Entity));

        var matchs = words.Select(word =>
                                        {
                                            var property = Expression.Property(parameter, "SomeField");
                                            var toLower = Expression.Call(property, "ToLower", new Type[] {});
                                            var contains = Expression.Call(toLower, "Contains",
                                                                            new Type[]{},
                                                                            Expression.Constant(word));
                                            return contains;
                                        }).OfType();

        var body = matchs.Aggregate(Expression.Or);

        return Expression.Lambda>(body, new[] {parameter});
    } 
}

Please let me know if I should add more information to this answer.