MVC FileContentResult-适用于DOC而非PDF

Question

I have the following ActionResult:

[Authorize]
public ActionResult DownloadFile(Guid id)
{
    AdjusterFile file = (from f in db.AdjusterFiles
                         join a in db.Adjusters
                         on f.adjusterID equals a.id
                         join u in db.Users
                         on a.userID equals u.id
                         where u.username == HttpContext.User.Identity.Name
                         && f.id == id
                         select f)
                        .FirstOrDefault();

    return new FileContentResult(file.fileContent.ToArray(), file.fileContentType);
}

It works perfectly for word documents (DOC/DOCX). However, whenever I try to download PDFs which are uploaded by the same process, it says, " Failed to load PDF document " in Chrome. In IE, it says, " The file is damaged and could not be repaired ."

The content type is "application/pdf."

How can I download PDFs in MVC?

Relevant file upload code:

using (MemoryStream ms = new MemoryStream())
{
    file.InputStream.CopyTo(ms);
    byte[] array = ms.GetBuffer();

    AdjusterFile newFile = new AdjusterFile();

    newFile.id = Guid.NewGuid();
    newFile.adjusterID = adj.id;
    newFile.type = "eo";
    newFile.fileName = file.FileName;
    newFile.fileContent = array;
    newFile.fileContentType = file.ContentType;

    db.AdjusterFiles.InsertOnSubmit(newFile);
}

Answer 1

You don't need a MemoryStream, try like this:

byte[] array = new byte[file.ContentLength];
file.InputStream.Read(array, 0, array.Length);

AdjusterFile newFile = new AdjusterFile();

newFile.id = Guid.NewGuid();
newFile.adjusterID = adj.id;
newFile.type = "eo";
newFile.fileName = file.FileName;
newFile.fileContent = array;
newFile.fileContentType = file.ContentType;

db.AdjusterFiles.InsertOnSubmit(newFile);

The reason why your code doesn't work lies in the following quote from the MSDN documentation of the GetBytes method that you are using on the MemoryStream:

Note that the buffer contains allocated bytes which might be unused. For example, if the string "test" is written into the MemoryStream object, the length of the buffer returned from GetBuffer is 256, not 4, with 252 bytes unused. To obtain only the data in the buffer, use the ToArray method; however, ToArray creates a copy of the data in memory.

So basically with the GetBytes method you might not always get the exact bytes you have written to the Stream. Alternatively you could have used the ms.ToArray() method which would have behaved correctly in your scenario, but honestly you don't need this MemoryStream at all. You are just allocating some unnecessary space where you could directly read the contents of the upload file into a byte array as shown in my answer.

Important remark: I hope you realize that by loading the entire byte array in-memory, the memory consumption could grow pretty fast on your webserver especially if you start working with big files. The ideal solution would have been to store the file either on the file system or if you are using MS SQL 2008 or higher take advantage of the new FILESTREAM type.