WPF使用WinSCP实现FTP下载

<WPFdev:Window x:Class="WpfApp1.Window1"
        xmlns="Http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlfORMats.org/markup-compatibility/2006"
        xmlns:wpfdev="https://GitHub.com/WPFDevelopersOrg/WPFDevelopers"
        xmlns:local="clr-namespace:WpfApp1"
        mc:Ignorable="d" windowstyle="ToolWindow"
        Title="WinSCP - FTP" Height="450" Width="800">
    <Grid>
        <WrapPanel VerticalAlignment="Center"
                   HorizontalAlignment="Center">
            <TextBlock Name="myTextBlock" Margin="10,0" VerticalAlignment="Center"/>
            <wpfdev:CircularProgressBar Name="myCircularProgressBar" 
                                        BrushStrokeThickness="2"
                                        StrokeThickness="5"
                                        Size="20,20"
                                        BorderBrush="#42ABAC" 
                                        Background="#E14D5F"
                                        Value="0"/>
            <Button Style="{StaticResource PrimaryButton}" Margin="10,0" Content="Download" Click="Button_Click"/>
        </WrapPanel>
    </Grid>
</wpfdev:Window>

using System;
using System.IO;
using System.Threading.Tasks;
using System.Windows;
using WinSCP;

namespace WpfApp1
{
    /// <summary>
    /// Window1.xaml 的交互逻辑
    /// </summary>
    public partial class Window1
    {
        public Window1()
        {
            InitializeComponent();
        }

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            myCircularProgressBar.Value = 0;
            Task.Run(() =>
            {
                Download();
            });
        }
        bool Download()
        {
            try
            {
                
                SessionOptions sessionOptions = new SessionOptions
                {
                    Protocol = Protocol.Ftp,
                    HostName = "127.0.0.1",
                    UserName = "wpfdevelopers",
                    PassWord = "wpfdevelopers",

                };
                string localPath = System.IO.Path.Combine(AppDomain.CurrentDomain.BaseDirectory,"packages");
                if (Directory.Exists(localPath))
                    DeleteDirectory(localPath);
                string remotePath = "packages";
                using (Session session = new Session())
                {
                    session.FileTransferProgress += Session_FileTransferProgress;
                    session.Open(sessionOptions);
                    TransferOptions transferOptions = new TransferOptions();
                    transferOptions.TransferMode = TransferMode.Binary;
                    TransferOperationResult transferResult = session.GetFiles(remotePath, localPath, false, transferOptions);
                    transferResult.Check();
                }
                return true;
            }
            catch (Exception)
            {
                return false;
            }
        }
        void DeleteDirectory(string target_dir)
        {
            string[] files = Directory.GetFiles(target_dir);
            string[] dirs = Directory.GetDirectories(target_dir);
            foreach (string file in files)
            {
                File.SetAttributes(file, FileAttributes.Normal);
                File.Delete(file);
            }
            foreach (string dir in dirs)
            {
                DeleteDirectory(dir);
            }
            Directory.Delete(target_dir, false);
        }
        private void Session_FileTransferProgress(object sender, FileTransferProgressEventArgs e)
        {
            Dispatcher.BeginInvoke(new Action(() =>
            {
               
                var value = (int)(e.OverallProgress * 100);
                myCircularProgressBar.Value = value;
                if (value == 100)
                    myTextBlock.Text = "文件已经全部下载完成";
                else
                    myTextBlock.Text = $"正在下载文件 {System.IO.Path.GetFileName(e.FileName)}";
            }));

        }
    }
}