asp.net-core-mvc - MVC 6 HttpPostedFileBase？

Question

我正在尝试使用上传图片MVC 6；但是，我找不到课程HttpPostedFileBase。我已经检查GitHub并没有任何运气。有谁知道上传文件的正确方法MVC6？

Answer 1

MVC 6 使用了另一种机制来上传文件。您可以在GitHub或其他 来源获得更多示例。只需IFormFile用作您的操作或文件集合的参数，或者IFormFileCollection如果您想同时上传几个文件：

public async Task<IActionResult> UploadSingle(IFormFile file)
{
    FileDetails fileDetails;
    using (var reader = new StreamReader(file.OpenReadStream()))
    {
        var fileContent = reader.ReadToEnd();
        var parsedContentDisposition = ContentDispositionHeaderValue.Parse(file.ContentDisposition);
        var fileName = parsedContentDisposition.FileName;
    }
    ...
}

[HttpPost]
public async Task<IActionResult> UploadMultiple(ICollection<IFormFile> files)
{
    var uploads = Path.Combine(_environment.WebRootPath,"uploads"); 
    foreach(var file in files)
    {
        if(file.Length > 0)
        {
            var fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');
            await file.SaveAsAsync(Path.Combine(uploads,fileName));
        }
        ...
    }
}

IFormFile您可以在asp.net 来源中查看当前合同。另请参阅ContentDispositionHeaderValue其他文件信息。

Answer 2

MVC6中没有HttpPostedFileBase。你可以IFormFile改用。

示例：https ://github.com/aspnet/Mvc/blob/dev/test/WebSites/ModelBindingWebSite/Controllers/FileUploadController.cs

来自上述链接的片段：

public FileDetails UploadSingle(IFormFile file)
{
    FileDetails fileDetails;
    using (var reader = new StreamReader(file.OpenReadStream()))
    {
        var fileContent = reader.ReadToEnd();
        var parsedContentDisposition = ContentDispositionHeaderValue.Parse(file.ContentDisposition);
        fileDetails = new FileDetails
        {
            Filename = parsedContentDisposition.FileName,
            Content = fileContent
        };
    }

    return fileDetails;
}

Answer 3

我搜索了很长一段时间，试图在 .net 核心中将其拼凑起来，最终得到以下结果。接下来将进行 Base64 转换，以便检索和显示更容易一些。我使用 IFormFileCollection 来处理多个文件。

[HttpPost]
    public async Task<IActionResult> Create(IFormFileCollection files)
    {

        Models.File fileIn = new Models.File();
        if(model != null && files != null)
        {
            foreach (var file in files)
            {
                if (file.Length > 0)
                {
                  var fileName = ContentDispositionHeaderValue.Parse(file.ContentDisposition).FileName.Trim('"');

                        byte[] fileBytes = null;
                        using (var fileStream = file.OpenReadStream())
                        using (var ms = new MemoryStream())
                        {
                            fileStream.CopyTo(ms);
                            fileBytes = ms.ToArray();
                            //string s = Convert.ToBase64String(fileBytes);
                            // act on the Base64 data
                        }


                        fileIn.Filename = fileName;
                        fileIn.FileLength = Convert.ToInt32(file.Length);
                        fileIn.FileType = file.ContentType;
                        fileIn.FileTypeId = model.FileTypeId;
                        fileIn.FileData = fileBytes;
                        _context.Add(fileIn);
                        await _context.SaveChangesAsync();
                }
            }
        }
        return View();
    }

编辑

以下是将文件返回到列表然后下载。

public JsonResult GetAllFiles()
    {

        var files = _context.File
            .Include(a => a.FileCategory)
            .Select(a => new
            {
                id = a.Id.ToString(),
                fileName = a.Filename,
                fileData = a.FileData,
                fileType = a.FileType,
                friendlyName = a.FriendlyName,
                fileCategory = a.FileCategory.Name.ToLower()
            }).ToList();

       return Json(files);
    }

    public FileStreamResult DownloadFileById(int id)
    {
        // Fetching file encoded code from database.
        var file = _context.File.SingleOrDefault(f => f.Id == id);
        var fileData = file.FileData;
        var fileName = file.Filename;

        // Converting to code to byte array
        byte[] bytes = Convert.FromBase64String(fileData);

        // Converting byte array to memory stream.
        MemoryStream stream = new MemoryStream(bytes);

        // Create final file stream result.
        FileStreamResult fileStream = new FileStreamResult(stream, "*/*");

        // File name with file extension.
        fileStream.FileDownloadName = fileName;
        return fileStream;
    }