An C# auxiliary class to easily create URLs with parameters

UrlFactory.cs

public class UrlFactory
{
    private Dictionary<string, string> _parameters;
    private string _url;

    public UrlFactory(string url)
    {
        _url = url;
        _parameters = new Dictionary<string, string>();
    }

    public void AddParameter(string key, string value)
    {
        _parameters.Add(key, value);
    }

    public string GetFullUrl()
    {
        var url = _url;

        if (_parameters.Count == 0)
            return url;

        var urlParameters = _parameters.Select(parameter => {
            var key = WebUtility.UrlEncode(parameter.Key);
            var value = WebUtility.UrlEncode(parameter.Value);

            return $"{key}={value}";
        });

        return $"{url}?{string.Join("&", urlParameters)}";
    }
}

Usage example:

var url = new UrlFactory("www.myapi.com/customer");
url.AddParameter("name", "Mr. Potato");
url.AddParameter("age", "32");

Console.WriteLine(url.GetFullUrl());
// www.myapi.com/customer?name=Mr.%20Potato&age=32