这是一个正常工作的dotNetFiddle: https://dotnetfiddle.net /6Zq5Ry

这是代码:

Here's a working dotNetFiddle: https://dotnetfiddle.net/6Zq5Ry

Here's the code:

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

public class Program
{
    public static void Main()
    {
        string json = @"{
                      'data': {
                        '4': {
                          'id': '12',
                          'email': 'lachlan12@somedomain.com',
                          'first_name': 'lachlan'
                          },
                        '5': {
                          'id': '15',
                          'email': 'appuswamy15email@somedomain.com',
                          'first_name': 'appuswamy'
                          }
                       }
                    }";

        var data = JsonConvert.DeserializeObject<RootObject>(json);
        Console.WriteLine("# of items deserialized : {0}", data.DataItems.Count);
        foreach ( var item in data.DataItems)
        {
            Console.WriteLine("  Item Key {0}: ", item.Key);
            Console.WriteLine("    id: {0}", item.Value.id);
            Console.WriteLine("    email: {0}", item.Value.email);
            Console.WriteLine("    first_name: {0}", item.Value.first_name);
        }
    }
}

public class RootObject
{
    [JsonProperty(PropertyName = "data")]
    public Dictionary<string,DataItem> DataItems { get; set; }
}

public class DataItem
{
    public string id { get; set; }
    public string email { get; set; }
    public string first_name { get; set; }
}

这是输出: