Program.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp2
{
    class Program
    {
        static void Main(string[] args)
        {
            string s = "abcd %(dbac) acd";
            var dict = new Dictionary<string, object>();
            dict.Add("dbac", 124);
            Console.WriteLine( RepalceTokenString(s, dict));
            Console.ReadLine();
        }

        static string RepalceTokenString(string s, Dictionary<string, object> dict)
        {
            foreach (var item in dict)
            {
                string token = "%(" + item.Key + ")";
                s = s.Replace(token, item.Value.ToString());

            }
            return s;
        }
    }
}