Question: The object has 139 fields; the string initializer may have some or all of these fields. It is formatted like this: "FirstName":"Bart","LastName":"Simpson","Company":"Fat Tony's","Address":"55 Maple Drive" etc. I could just look for the fields like this:

```
if (initializerString.contains("FirstName:") 
   FirstName="get the next series of chars until the ", or end of string

```

and so forth. But is there a more compact way to do this?

Answer: 
Seeing as your format is incredibly similar to JSON (except for the lack of braces, actually), as people commented you'll fare better by using JSON.NET. 

If you have complete control over this string, just transform it into a json and deserialize it:

```
JsonConvert.DeserializeObject<YourClass>(yourString);

```

It will automatically set the correct properties while deserializing your data.

In case you don't have control of this format, and you need to parse it anyway, just put up the braces and you're good:

```
JsonConvert.DeserializeObject<YourClass>("{" + yourString + "}");

```

And if you don't have a specific class for this, you can also replace `YourClass` for a `Dictionary<string,object>`

You'll find this library as `Newtonsoft.Json`, and I believe it's the most popular library for dealing with JSON data.

I've made a working example so you can see it in action (note that I kept your string format, but please try to use straight json):

```
using System;
using System.Linq;
using System.Collections.Generic;
using Newtonsoft.Json;

public class Program
{
    public class Information
    {
        public string FirstName{get;set;}
        public string LastName{get;set;}
        public string Company{get;set;}
        public string Address{get;set;}
    }

    public static void Main()
    {
        string myObject =  "\"FirstName\":\"Bart\",\"LastName\":\"Simpson\",\"Company\":\"Fat Tony's\",\"Address\":\"55 Maple Drive\"";
        var converted = JsonConvert.DeserializeObject<Dictionary<string, object>>("{"+myObject+"}");
        var converted2 = JsonConvert.DeserializeObject<Information>("{"+myObject+"}");
        Console.WriteLine(String.Join("\n", converted.Select(c=> c.Key + ": " + c.Value)));
        Console.WriteLine(converted2.FirstName);
    }
}

```

And here's a bonus fiddle:

<https://dotnetfiddle.net/fudUYZ>
Using regex you could do:

```
 string firstName = Regex.Match(yourstring,@"(?<=""FirstName"":"").*?(?="")").Value;

```

However this really looks like a json string and there are easier ways to get your data.