Expressions

gistfile1.cs

using System;
using System.Linq.Expressions;
using NUnit.Framework;

namespace ClassLibrary1
{
    [TestFixture]
    public class Class2
    {
        [Test]
        public void CanReadExpression()
        {
            var filter = new Filter();

            filter.Run(x => x.Body.Equals("test"));
            filter.Run(x => !x.Body.Equals("test"));
            filter.Run(x => x.Body == "test");
        }
    }

    public class Filter
    {
        public void Run(Expression<Func<Message, bool>> expression)
        {
            var body = expression.Body;

            if (body is MethodCallExpression)
            {
                var methodCallExpression = body as MethodCallExpression;
                var method = methodCallExpression.Method;

                Console.WriteLine("Method name {0}", method.Name);
            }
            else if (body is UnaryExpression)
            {
                var unaryExpression = body as UnaryExpression;

                var nodeType = unaryExpression.NodeType;
              
                if (unaryExpression.Operand is MethodCallExpression)
                {
                    var methodCallExpression = unaryExpression.Operand as MethodCallExpression;
                    var method = methodCallExpression.Method;

                    Console.WriteLine("Method name {0}", method.Name);
                }

                Console.WriteLine("Nodetype {0}", nodeType);
            }
            else if (body is BinaryExpression)
            {
                var binaryExpression = body as BinaryExpression;
                var nodeType = binaryExpression.NodeType;
           
                Console.WriteLine("Nodetype {0}", nodeType);
            }
        }
    }

    public class Message
    {
        public string Body { get; set; }
    }
}