Common/Internet/UrlHelper.cs

using System;

namespace Common.Internet
{
    public static class UrlHelper
    {
        public static string GetAbsoluteUrlString(string baseUrl, string url)
        {
            var uri = new Uri(url, UriKind.RelativeOrAbsolute);
            if (!uri.IsAbsoluteUri)
                uri = new Uri(new Uri(baseUrl), uri);
            return uri.ToString();
        }
    }
}