C# Winfrom中 下载PDF文件

 private void Button1_Click(object sender, EventArgs e)
 {
     string Server = "服务器URL";
     string username = "账户";
     string password = "密码";
     string remote = "服务器路径";
     string local = "D:\\Debug"; // 本地文件夹路径
     // 创建本地文件夹（如果不存在）
     if (!Directory.Exists(local))
     {
         Directory.CreateDirectory(local);
     }
     try
     {
         // 连接到 FTP 服务器
         using (WebClient ftpClient = new WebClient())
         {
             ftpClient.Credentials = new NetworkCredential(username, password);
             // 获取 FTP 目录中的文件列表
             string[] fileList = ftpClient.DownloadDirectoryList(remote);
             // 下载并保存每个文件
             foreach (string file in fileList)
             {
                 string remoteFilePath= remote + "/" + file;
                 string localFilePath =
                 Path.Combine(local, file);
                 // 下载文件
                 ftpClient.DownloadFile
                 (remoteFilePath, localFilePath);
                 // 释放资源
                 ftpClient.Dispose();
             }
             MessageBox.Show("下载完成！");
         }
     }
     catch (Exception ex)
     {
         MessageBox.Show("出现错误：" + ex.Message);
     }
 }