using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Reflection;

​

public class Program

{

    public static void Main()

    {

​

        Console.WriteLine(SerializeAsFormData(new SampleType() { PropInt = 1, PropString = "hola", PropDateTime=DateTime.UtcNow }));

    }

​

    public class SampleType

    {

        public int PropInt { get; set; }

        public string PropString { get; set; }

        public DateTime PropDateTime { get; set; }

        public bool PropBool {get; set;}

    }

​

    public static string SerializeAsFormData(object obj)

    {

        var keyValuePairList = new List<KeyValuePair<string, string>>();

        foreach(PropertyInfo propertyInfo in obj.GetType().GetProperties())

        {

            keyValuePairList.Add(new KeyValuePair<string, string>(propertyInfo.Name, HttpUtility.UrlEncode(propertyInfo.GetValue(obj, null).ToString())));

        }

        return String.Join('&', keyValuePairList.Select(x => new string(x.Key + "=" + x.Value)));

    }

}