winform复制文件到指定目录

//打开文件对话框并获取选择的文件
private List<string> OpenImagesDialog(bool isMulti = true)
{
    var openFileDialog = new OpenFileDialog();
    const string imgExts = "图像文件 (*.bmp;*.ico;*.gif;*.jpeg;*.jpg;*.png)|*.bmp;*.ico;*.gif;*.jpeg;*.jpg;*.png";
    openFileDialog.Filter = imgExts;//可选择的文件格式 (|之前为显示，之后为控制后缀显示)
    openFileDialog.Multiselect = isMulti;//多选设置
    openFileDialog.RestoreDirectory = true;
    openFileDialog.FilterIndex = 1;
    var result = new List<string>();
    if (openFileDialog.ShowDialog() == DialogResult.OK)
    {
        result.AddRange(openFileDialog.FileNames);
    }
    return result;
}

  /// <summary>
  /// 复制文件到指定目录并重命名
  /// </summary>
  /// <param name="sourcePaths">要复制的文件路径集合</param>
  /// <param name="targetDir">目标目录</param>
  /// <returns>Item1:对应路径，Item2:失败文件路径</returns>
  public static Tuple<Dictionary<string, string>, List<string>> CopyFileToDir(List<string> sourcePaths, string targetDir)
  {
      if (!Directory.Exists(targetDir))
      {
          Directory.CreateDirectory(targetDir);
      }
      var errorFiles = new List<string>();
      var saveDirs = new Dictionary<string, string>();
      sourcePaths.ForEach(item =>
      {
          //路径不存在或者路径已存在则失败
          if (!File.Exists(item) || saveDirs.ContainsKey(item))
          {
              errorFiles.Add(item);
          }
          else
          {
              var saveName = Guid.NewGuid() + Path.GetExtension(item);
              var savePath = Path.Combine(targetDir, saveName);
              File.Copy(item, savePath);
              saveDirs.Add(item, savePath);
          }
      });
      var result = new Tuple<Dictionary<string, string>, List<string>>(saveDirs, errorFiles);
      return result;
  }

  var selectImgs = OpenImagesDialog(true);//打开文件对话框并获取选择的所有文件
  var result = FileHelper.CopyFileToDir(selectImgs, txtSaveDir.Text);
  //result.Item1 [{源文件路径:目标路径}]
  //result.Item2 [失败路径1,失败路径2]