using System;

using System.Collections.Generic;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        string messageTemplate = "Milestone \"%Milestone%\" has been reassigned from %OLD_OWNER% to %NEW_OWNER%.";

​

        MacroData macroData = new MacroData();

        macroData.AddValue("Milestone", "Notification message body text replacement");

        macroData.AddValue("Old_Owner", "Brian");

        macroData.AddValue("New_Owner", "Satish");

        string filledInTemplate = new TemplateBuilder(messageTemplate, macroData).FillInTemplate();

        Console.WriteLine(filledInTemplate);

    }

​

}

​

public class TemplateBuilder

{

    private static Regex templateMacroRegex = new Regex(@"%(?<key>[A-z_\-]+)%");

    private string _template;

    private MacroData _data;

​

    public TemplateBuilder(string messageTemplate, MacroData data)

    {

        _template = messageTemplate;

        _data = data;

    }

    public string FillInTemplate()

    {

        MatchEvaluator myEvaluator = new MatchEvaluator(ReplaceCC);

        return templateMacroRegex.Replace(_template, myEvaluator);

    }

    public  string ReplaceCC(Match m)

    {

        string macroName = m.Groups["key"].Value;

        return _data.GetValueForMacro(macroName);   

    }

​

}

​

public class MacroData

{

    Dictionary<string, string> _data = new Dictionary<string, string>(StringComparer.InvariantCultureIgnoreCase);

    public MacroData()

    {

    }

    public void AddValue(String key, string val)

    {

        _data.Add(key, val); // Log an error if there is a duplicate key

    }

    public string GetValueForMacro(string macroName)

    {

        string val = null;

        if (_data.TryGetValue(macroName, out val))

        {

            return val;

        }

        else

        {

            // Log error, but maybe don't blow up

        }

        return null;

    }

}