using System;

using System.Text.RegularExpressions;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var pattern = @"\{([^\}]+)\}";

        var input = "{portal}/sfsdl";

        var dict = new Dictionary<string,string>() {

            { "portal", "ttx.com" } 

        };

        var output = Regex.Replace(input, pattern, (m) => { 

            return dict[m.Groups[1].Value];

        });

        Console.WriteLine("Pattern: {0}", pattern);

        Console.WriteLine("Input: {0}", input);

        Console.WriteLine("Output: {0}", output);

    }

}