using System.Net;

WebClient webClient = new WebClient();
webClient.DownloadFile("http://mysite.com/myfile.txt", @"c:\myfile.txt");

试试这个:

private void downloadFile(string url)
{
     string file = System.IO.Path.GetFileName(url);
     WebClient cln = new WebClient();
     cln.DownloadFile(url, file);
}

using System.Net;

WebClient webClient = new WebClient();
webClient.DownloadFile("http://mysite.com/myfile.txt", @"c:\myfile.txt");

using (var client = new WebClient())
{
    client.DownloadFile("http://example.com/file/song/a.mpeg", "a.mpeg");
}

使用GetIsNetworkAvailable()检查网络连接，以避免在未连接到网络时创建空文件。

if (System.Net.NetworkInformation.NetworkInterface.GetIsNetworkAvailable())
{
    using (System.Net.WebClient client = new System.Net.WebClient())
    {                        
          client.DownloadFileAsync(new Uri("http://www.examplesite.com/test.txt"),
          "D:\\test.txt");
    }                  
}

这是我的解决方案，效果很好:

public static void DownloadFile(string url, string pathToSaveFile)
        {
            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
            // or: ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;

            using (WebDownload client = new WebDownload())
            {
                client.Headers["User-Agent"] = "User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/56.0.2924.87 Safari/537.36";
                client.DownloadFile(new Uri(url), pathToSaveFile);
            }
        }
    
    public class WebDownload : WebClient
        {
            protected override WebRequest GetWebRequest(Uri address)
            {
                HttpWebRequest request = (HttpWebRequest)base.GetWebRequest(address);
                if (request != null)
                {
                    request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
                }
                return request;
            }
        }