static void Main(string[] args)

        {

            string[] exps = new string[]

            {

                @" ""keyA"" !=""valA"" ",

                @"keyA !=""valA""",

                @"(keyA ==""valA"")",

                @"keyA ==""val1"" || key2 ==""val2""",

                @"key1 ==""val1"" && key2 ==""val2""",

                @" key1 !=""val1"" || key2 ==""val2""&& key3 != ""val3""",

                @"(key1 ==""val1"" || key2 ==""val2"")&& key3 != ""val3""",

            };

            string pattern = @"(?<key>[\w\d_]+)""*\s*(?<equality>==|!=)\s*""*(?<value>[\w\d_]+)";

            foreach (var exp in exps)

            {

                // Parses to get the parameters.

                string formattedExp = exp;

                var matches = Regex.Matches(exp, pattern);

                ParameterExpression[] parameters = new ParameterExpression[matches.Count];

                for (int i =; i < matches.Count; i++)

                {

                    Debug.Write(" key[" + matches[i].Groups["key"].Value);

                    Debug.Write("] equality[" + matches[i].Groups["equality"].Value);

                    Debug.Write("] value[" + matches[i].Groups["value"].Value +"]\t\n");

                    parameters[i] = Expression.Parameter(typeof(string), matches[i].Groups["key"].Value);

                    // Removing " if it has in keys.

                    if (exp.Contains(string.Format(@"""{0}""", matches[i].Groups["key"].Value)))

                    {

                        formattedExp = exp.Replace(string.Format(@"""{0}""", matches[i].Groups["key"].Value), matches[i].Groups["key"].Value);

                    }

                }

                var e = System.Linq.Dynamic.DynamicExpression.ParseLambda(parameters, null, formattedExp);

                string[] GotValues = new string[matches.Count];

               if (GotValues.Length == )

               {

                   GotValues[] = "val1";

                   GotValues[] = "val2";

               }

               if (GotValues.Length == )

               {

                   GotValues[] = "val1";

                   GotValues[] = "val2";

                   GotValues[] = "val3";

               }

                var result = e.Compile().DynamicInvoke(GotValues);

                Debug.WriteLine("{0} ---> {1}", e.ToString(), result);

            }

        }