How can I create a more user-friendly string.format syntax?

Question

I need to create a very long string in a program, and have been using String.Format. The problem I am facing is keeping track of all the numbers when you have more than 8-10 parameters.

Is it possible to create some form of overload that will accept a syntax similar to this?

String.Format("You are {age} years old and your last name is {name} ", {age = "18", name = "Foo"}); 

Answer 1

How about the following, which works both for anonymous types (the example below), or regular types (domain entities, etc):

static void Main() {     string s = Format("You are {age} years old and your last name is {name} ",         new {age = 18, name = "Foo"}); } 

using:

static readonly Regex rePattern = new Regex(     @"(\{+)([^\}]+)(\}+)", RegexOptions.Compiled); static string Format(string pattern, object template) {     if (template == null) throw new ArgumentNullException();     Type type = template.GetType();     var cache = new Dictionary<string, string>();     return rePattern.Replace(pattern, match =>     {         int lCount = match.Groups[1].Value.Length,             rCount = match.Groups[3].Value.Length;         if ((lCount % 2) != (rCount % 2)) throw new InvalidOperationException("Unbalanced braces");         string lBrace = lCount == 1 ? "" : new string('{', lCount / 2),             rBrace = rCount == 1 ? "" : new string('}', rCount / 2);          string key = match.Groups[2].Value, value;         if(lCount % 2 == 0) {             value = key;         } else {             if (!cache.TryGetValue(key, out value))             {                 var prop = type.GetProperty(key);                 if (prop == null)                 {                     throw new ArgumentException("Not found: " + key, "pattern");                 }                 value = Convert.ToString(prop.GetValue(template, null));                 cache.Add(key, value);             }         }         return lBrace + value + rBrace;     }); }