用于从服务器下载文件的 Html 正确文件路径

Question

我已经完成了将文件保存到服务器文件夹的功能，**我现在正在尝试使用HTML download 从服务器取回文件，但还没有找到获取正确文件路径的方法.

在将文件存储在服务器的文件夹中后，使用实体框架将文件路径保存在数据库中，我使用filePath = /VisitReportAttachments/1ea2b64e-545d-4c50-ae7d-eefa7178d310.png 从数据库中检索了file。但是这个 filePath 不能正常工作。

 <a href="@file.Path" download="@file.name">Click here to download</a>
//file.Path = /VisitReportAttachments/1ea2b64e-545d-4c50-ae7d-eefa7178d310.png

我收到一个错误：Failed - No file

看看在 Controller 的 SaveFile 代码中创建 FilePath path：

private void SaveFile(HttpPostedFileBase file)
{
    string serverPath = "\\VisitReportAttachments";
      if (file!= null)
        {
        if (!Directory.Exists(serverPath))
        {
            Directory.CreateDirectory(serverPath);
        }
         var fileName = Guid.NewGuid()+ Path.GetExtension(file.FileName);
         var path = Path.Combine("\\", new DirectoryInfo(serverPath).Name, fileName);
         path = relativePath.Replace(@"\", "/"); //this path is stored to DB
          ....
       //As I mentioned: save file to Server is done. I simply post the code that create the filepath in SQL DB while file is storing to Server*
        }
}

FilePath 存储在 DB 中，例如：/VisitReportAttachments/1ea2b64e-545d-4c50-ae7d-eefa7178d310.png

需要帮助！

Answer 1

通过使用Server.MapPath 将文件路径映射到正确的路径找到解决方案。

我没有在 HTML 视图中使用可下载的链接，而是在控制器中创建了下载功能：

[HttpPost]
        [Authorize]
        public ActionResult DownloadAttachment()
        {
            return Json(true);
        }

        [HttpGet]
        public ActionResult Download(Guid? attachmentId)
        {
            var visitAttachment = _visitAttachmentService.FindOne(x => x.Id == attachmentId);
            try
            {
                var serverPath = Server.MapPath(visitAttachment.Path);
                byte[] fileBytes = System.IO.File.ReadAllBytes(serverPath);
                return File(fileBytes, System.Net.Mime.MediaTypeNames.Application.Octet, visitAttachment.AttachmentName);

            }
            catch
            {
                return File(Encoding.UTF8.GetBytes(""), System.Net.Mime.MediaTypeNames.Application.Octet, visitAttachment.AttachmentName);
            }

        }

在视图中调用这个方法：

<a href="" onclick="Download('@file.Id');">@file.AttachmentName</a>

<script>
    function Download(attachmentId) {
            var url = '/Visits/DownloadAttachment';
            $.post(url,
                {
                    //                  FilePath: filePath
                },
                function (data) {
                    var response = JSON.parse(data);
                    window.location = '/Visits/Download?attachmentId=' + attachmentId;
                },
                "json");
        }
    </script>

现在完美运行。

Answer 2

您的private string SaveFile(HttpPostedFileBase file) 方法应该返回一个NewFile 模型对象，该对象反映了您数据库中的实体。 private NewFile SaveFile(HttpPostedFileBase file)

public class NewFile
{
   public int NewFileId { get; set; } 
   public string FileName { get; set; }
   public string FilePath { get; set; }
}

保存文件时，您需要执行类似于以下代码的操作：

using (var db = new YourDbContext())
{
   var newFile = new NewFile { FileName = fileName, FilePath = path };

   var savedFile = db.Add(newFile);

   db.SaveChanges();

   return savedFile;   // here is the object you can return to the view and access 
                       // its properties
}

Answer 3

    private string SaveFile(HttpPostedFileBase file)
    {
        if (file == null)
            return string.Empty;

        string saveFolder = "VisitReportAttachments";

        string fileName = fileName = Guid.NewGuid() + Path.GetExtension(file.FileName);
        string serverFolderPath = AppDomain.CurrentDomain.BaseDirectory + "/" + saveFolder;
        string savePath = serverFolderPath + "/" + fileName;


        if (!Directory.Exists(serverFolderPath))
            Directory.CreateDirectory(serverFolderPath);

        file.SaveAs(savePath);

        return Url.Content($"~/{saveFolder}/{fileName}");
    }

Answer 4

您没有保存文件夹中的文件。 在代码中添加以下行

file.SaveAs(serverPath + file.FileName);

所以你的 C# 代码会是这样的

private string SaveFile(HttpPostedFileBase file)
{
    string serverPath = "\\VisitReportAttachments";
      if (file!= null)
        {
        if (!Directory.Exists(serverPath))
        {
            Directory.CreateDirectory(serverPath);
        }
         var fileName = Guid.NewGuid()+ Path.GetExtension(file.FileName);
         var path = Path.Combine("\\", new DirectoryInfo(serverPath).Name, fileName);

         file.SaveAs(serverPath + file.FileName);

         path = relativePath.Replace(@"\", "/");

         return path;
        }
         return string.Empty;
}