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

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

您可能需要在文件下载期间了解状态并更新ProgressBar，或者在发出请求之前使用凭据。

下面是一个包含这些选项的示例。Lambda符号和字符串插值已被使用:

using System.Net;
// ...

using (WebClient client = new WebClient()) {
    Uri ur = new Uri("http://remotehost.do/images/img.jpg");

    //client.Credentials = new NetworkCredential("username", "password");
    String credentials = Convert.ToBase64String(Encoding.ASCII.GetBytes("Username" + ":" + "MyNewPassword"));
    client.Headers[HttpRequestHeader.Authorization] = $"Basic {credentials}";

    client.DownloadProgressChanged += (o, e) =>
    {
        Console.WriteLine($"Download status: {e.ProgressPercentage}%.");

        // updating the UI
        Dispatcher.Invoke(() => {
            progressBar.Value = e.ProgressPercentage;
        });
    };

    client.DownloadDataCompleted += (o, e) => 
    {
        Console.WriteLine("Download finished!");
    };

    client.DownloadFileAsync(ur, @"C:\path\newImage.jpg");
}

using System.Net;

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

下面的代码包含下载文件的逻辑与原始名称

private string DownloadFile(string url)
    {

        HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
        string filename = "";
        string destinationpath = Environment;
        if (!Directory.Exists(destinationpath))
        {
            Directory.CreateDirectory(destinationpath);
        }
        using (HttpWebResponse response = (HttpWebResponse)request.GetResponseAsync().Result)
        {
            string path = response.Headers["Content-Disposition"];
            if (string.IsNullOrWhiteSpace(path))
            {
                var uri = new Uri(url);
                filename = Path.GetFileName(uri.LocalPath);
            }
            else
            {
                ContentDisposition contentDisposition = new ContentDisposition(path);
                filename = contentDisposition.FileName;

            }

            var responseStream = response.GetResponseStream();
            using (var fileStream = File.Create(System.IO.Path.Combine(destinationpath, filename)))
            {
                responseStream.CopyTo(fileStream);
            }
        }

        return Path.Combine(destinationpath, filename);
    }

static void Main(string[] args)
        {
            DownloadFileAsync().GetAwaiter();
 
            Console.WriteLine("File was downloaded");
            Console.Read();
        }
 
        private static async Task DownloadFileAsync()
        {
            WebClient client = new WebClient();
            await client.DownloadFileTaskAsync(new Uri("http://somesite.com/myfile.txt"), "mytxtFile.txt");
        }