从列表中删除文件后，文件上传控制会话不删除

Question

我为这个问题沮丧了几个星期，

我怎样才能为这个多文件上传做会话

  if (Session["FileUpload1"] == null && FileUploadQ2.HasFile)
        {
            Session["FileUpload1"] = FileUploadQ2;

            foreach (HttpPostedFile file in FileUploadQ2.PostedFiles)
            {
                listofuploadedfiles.Text += String.Format("<p><font color='black'>" + file.FileName + "</font><a class='close'><font color='red'>x</font><a>" + "</p>");

            }

        }

        else if (Session["FileUpload1"] != null && (!FileUploadQ2.HasFile))
        {
            FileUploadQ2 = (FileUpload)Session["FileUpload1"];

        }
        else if(FileUploadQ2.HasFile)
        {
            Session["FileUpload1"] = FileUploadQ2;
        }

Answer 1

正如@VDWWD 所指出的，您不应该将文件存储在 Session 对象中 - 而是将它们存储在磁盘上。您可以在下面找到该功能的快速实现。

    public interface IFileStorage
    {
        Task UploadFile(string fileName, Stream fileContent);
        void TryRemoveFile(string fileName, out bool fileRemoved);
        void GetFile(string fileName);
    }

    public class FileSystemStorage : IFileStorage
    {
        private readonly PhysicalFileProvider _fileProvider;
        private readonly ILogger<FileSystemStorage>_logger;

        public FileSystemStorage(IFileProvider fileProvider, ILogger<FileSystemStorage> logger)
        {
            _fileProvider = (PhysicalFileProvider)fileProvider;
            _logger = logger;
        }

        public void GetFile(string fileName)
        {
            throw new NotImplementedException();
        }

        public void TryRemoveFile(string fileName, out bool fileRemoved)
        {
            try
            {
                RemoveFile(fileName);
                fileRemoved = true;
            }
            catch(Exception ex)
            {
                _logger.LogError($"Couldnt remove file {fileName}: {ex.ToString()}" );
                fileRemoved = false;
            }
        }

        public async Task UploadFile(string fileName, Stream fileContent)
        {
            var filePath = Path.Combine(_fileProvider.Root, fileName);
            if (_fileProvider.GetFileInfo(filePath).Exists)
                throw new ArgumentException("Given file already exists!");

            _logger.LogInformation($"Saving file to: {filePath}..");
            using (Stream file = File.Create(filePath))
            {
                await fileContent.CopyToAsync(file);
                file.Flush();
            }

            _logger.LogInformation($"File: {filePath} saved successfully.");
        }
    }

在 Startup.cs 中，ConfigureServices 方法添加以下行以注入 FileSystemStorage：

IFileProvider physicalProvider = new PhysicalFileProvider(Path.Combine(Directory.GetCurrentDirectory(), "AppData"));
services.AddSingleton<IFileProvider>(physicalProvider);
services.AddTransient<IFileStorage, FileSystemStorage>();

然后在您的控制器构造函数中获取 FileSystemStorage 实例。