using System;
using System.Net;

namespace WebDownload
{
    public class WebDownload
    {
        public string Download(string Link, string Destination)
        {
            var status = @"Not Available";
            try
            {
                var wc = new WebClient();
                wc.DownloadFile(Link, Destination);
                status = @"OK";
            }
            catch (Exception ex)
            {
                status = ex.ToString();
            }
            return status;
        }
    }
}

using System;

namespace MyConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var wd = new WebDownload.WebDownload();
            var status = wd.Download(@"http://download.thinkbroadband.com/5MB.zip", @"D:\test\test.zip");
            Console.WriteLine(status);

            Console.Read();
        }
    }
}

using System;
using System.Net;

namespace WebDownload
{
    public class WebDownload
    {
        public event EventHandler<WebDownloadEventArgs> Error;
        public event EventHandler<WebDownloadEventArgs> FileDownload;

        public void Download(string Link, string Destination)
        {
            try
            {
                var request = (HttpWebRequest)System.Net.HttpWebRequest.Create(Link);
                request.Method = "HEAD";
                var response = (HttpWebResponse)request.GetResponse();

                if (response.ContentLength != -1)
                {
                    OnFileDownLoad(new WebDownloadEventArgs() { Status = @"FileDownload" });
                    var wc = new WebClient();
                    wc.DownloadFile(Link, Destination);
                    OnFileDownLoad(new WebDownloadEventArgs() { Status = @"Download completed" });
                }
                else
                {
                    OnFileDownLoad(new WebDownloadEventArgs() { Status = @"Not download content" });
                }
            }
            catch (Exception ex)
            {
                OnError(new WebDownloadEventArgs() { Status = ex.ToString() });
            }
        }

        private void OnFileDownLoad(WebDownloadEventArgs e)
        {
            if (FileDownload != null)
            {
                FileDownload(this, e);
            }
        }

        private void OnError(WebDownloadEventArgs e)
        {
            if (Error != null)
            {
                Error(this, e);
            }
        }
    }

    public class WebDownloadEventArgs : EventArgs
    {
        public string Status { get; set; }
    }
}

namespace MyConsoleApp
{
    class Program
    {
        static void Main(string[] args)
        {
            var link = @"http://www.google.com";
            var dest = @"D:\test\test.zip";

            var link2 = @"http://download.thinkbroadband.com/5MB.zip";
            var dest2 = @"D:\test\test2.zip";

            var link3 = @"http://test.test";
            var dest3 = @"D:\test\test3.zip";

            var wd = new WebDownload.WebDownload();
            wd.Error += wd_Error;
            wd.FileDownload += wd_FileDownload;

            wd.Download(link, dest);
            wd.Download(link2, dest2);
            wd.Download(link3, dest3);

            Console.Read();
        }

        static void wd_FileDownload(object sender, WebDownload.WebDownloadEventArgs e)
        {
            Console.WriteLine(e.Status);
        }

        static void wd_Error(object sender, WebDownload.WebDownloadEventArgs e)
        {
            Console.WriteLine(e.Status);
        }
    }
}