Question

下面的代码仅使用.net 2.0即可运行多年。现在它停止了，并且仅适用于.net 4.6或更高版本。保持不变。调试器在

上运行

client.DownloadFileAsync（新的Uri（sourceURL），目标）;

行。但不再下载任何内容。

using System;
using System.ComponentModel;
using System.Net;
using System.Windows.Forms;

namespace NewTest
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            StartDownload();
        }

        private void StartDownload()
        {
            using (WebClient client = new WebClient())
            {
                client.DownloadProgressChanged += new DownloadProgressChangedEventHandler(client_DownloadProgressChanged);
                client.DownloadFileCompleted += new AsyncCompletedEventHandler(client_DownloadFileCompleted);

                string destination = "Tools.exe";
                string sourceURL = "https://mysiteexample.com/download/Tools.exe";

                client.DownloadFileAsync(new Uri(sourceURL), destination);
            }
        }

        void client_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
        {
            progressBar1.Value = e.ProgressPercentage;
        }

        void client_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
        {
            MessageBox.Show("Done");
        }
    }
}

Answer 1

感谢Henk，我能够获得有关我的问题的更多信息。我的ISP开始需要TLS 1.2。所以我必须添加以下代码。现在工作正常。

ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;

因此，得到的代码是。

        using (WebClient client = new WebClient())
        {
            client.DownloadProgressChanged += new DownloadProgressChangedEventHandler(client_DownloadProgressChanged);
            client.DownloadFileCompleted += new AsyncCompletedEventHandler(client_DownloadFileCompleted);

            string destination = "Tools.exe";
            string sourceURL = "https://mysiteexample.com/download/Tools.exe";

            ServicePointManager.SecurityProtocol = (SecurityProtocolType)3072;                
            client.DownloadFileAsync(new Uri(sourceURL), destination);
        }

在.NET 2.0下工作的文件下载现在仅在.NET4.6下工作

1 个答案: