Get a list of JSON property names from a class to use in a query string

Question

If I have a C# model class that is used by JSON.net to bind data from a serialized JSON string, is there a way that I can create a query string from that class in order to make the initial request?

Model class example:

public class model {    [JsonProperty(PropertyName = "id")]    public long ID { get; set; }    [JsonProperty(PropertyName = "some_string")]    public string SomeString {get; set;}  } 

Querystring example:

baseUrl + uri + "&fields=id,some_string" + token 

So the essence of what I am trying to do is gather both "id" and "some_string" from the model object so i can dynamically create a the "&fields" arguments. Thanks!

Answer 1

@Leigh Shepperson has the right idea; however, you can do it with less code using LINQ. I would create a helper method like this:

using System.Linq; using System.Reflection; using Newtonsoft.Json; ...  public static string GetFields(Type modelType) {     return string.Join(",",         modelType.GetProperties()                  .Select(p => p.GetCustomAttribute<JsonPropertyAttribute>())                  .Select(jp => jp.PropertyName)); } 

You can use it like this:

var fields = "&fields=" + GetFields(typeof(model)); 

EDIT

If you're running under the 3.5 version of the .Net Framework such that you don't have the generic GetCustomAttribute<T> method available to you, you can do the same thing with the non-generic GetCustomAttributes() method instead, using it with SelectMany and Cast<T>:

    return string.Join(",",         modelType.GetProperties()                  .SelectMany(p => p.GetCustomAttributes(typeof(JsonPropertyAttribute))                                    .Cast<JsonPropertyAttribute>())                  .Select(jp => jp.PropertyName)                  .ToArray()); 

Answer 2

You can do this using reflection. This is the general idea:

using Newtonsoft.Json; using Newtonsoft.Json.Serialization; using System.Reflection;  namespace ConsoleApplication8 {     public class model     {         [JsonProperty(PropertyName = "id")]         public long ID { get; set; }          [JsonProperty(PropertyName = "some_string")]         public string SomeString { get; set; }     }      internal class Program     {         private static void Main(string[] args)         {             var model = new model();              var result = string.Empty;              PropertyInfo[] props = typeof(model).GetProperties();             foreach (PropertyInfo prop in props)             {                 foreach (object attr in prop.GetCustomAttributes(true))                 {                     result += (attr as JsonPropertyAttribute).PropertyName;                 }             }         }     } }