using System;

using System.Text;

using System.Collections.Specialized;

public static class Program

{

    public static Uri AttachParameters(this Uri uri, NameValueCollection parameters)

    {

        var stringBuilder = new StringBuilder();

        string str = "?";

        for (int index = 0; index < parameters.Count; ++index)

        {

            stringBuilder.Append(str + parameters.AllKeys[index] + "=" + parameters[index]);

            str = "&";

        }

        return new Uri(uri + stringBuilder.ToString());

    }

​

    public static void Main()

    {

        Uri uri = new Uri("https://portal.freightfriend.net/search/capacity/results/").AttachParameters(new NameValueCollection{

            {"token", "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJ1bmlxdWVfbmFtZSI6IjdhZGZkZjM2LTM5ODEtNDc3OS1iZGM3LTNmMjFlNTFiMjBiMSIsImV4cCI6MTU4NjQ1OTQ3NiwiZmlyc3RfbmFtZSI6IiIsImxhc3RfbmFtZSI6IiIsImVtYWlsIjoiYmlsbHlAY2hpY2Fnb2Jyb2tlcmFnZS5jb20iLCJ1c2VyX2lkIjoiIn0.lAFoeo5vVsWuhEtQOS8Y7R-5R0vCbFsym6D4uR9MUak"}, 

            {"olat", "39.940669"},

            {"olong", "-82.978592"},

            {"dlat", "42.212327"},

            {"dlong", "-83.347739"},

            {"equipment[]", "R"},

            {"equipment[]", "V"},

            {"origin", "Columbus,+OH"},

            {"destination", "Detroit,+MI"},

            {"puDate", "4/8/2020"},

            {"reference", "1245878"},

        });

        Console.WriteLine(uri.ToString());

    }

}