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sqlsql-serverimagefield

Read file from database


I am trying to download a file I have uploaded to an image field in my MS-SQL database. The problem is that when I try to open the file it just says System.Byte[] instead of containing the actual content.

UploadFiles is my class which contains the filename, id, filedata etc.

public void DownloadUploadedFile(Page sender, UploadFiles uf)
{
    sender.Response.Clear();
    sender.Response.ContentType = uf.FileType; 
    sender.Response.AddHeader("Content-Disposition",
        "attachment; filename=" + uf.FileName);
    sender.Response.BinaryWrite(uf.FileData); // the binary data
    sender.Response.End();
}

Here I retrieve the data from my database:

 while (reader.Read())
                    {
                        UploadFiles uf = new UploadFiles();
                        uf.FileData = encoding.GetBytes(reader["filedata"].ToString());
                        uf.FileName = reader["name"].ToString();
                        uf.FileType = reader["filetype"].ToString();
                        uf.FileId = Convert.ToInt32(reader["id"]);
                        return uf;
                    }

Solution

  • The

    uf.FileData = encoding.GetBytes(reader["filedata"].ToString());
    

    should be

    uf.FileData = (byte[])reader["filedata"];
    

    The data returned is a byte array, and you call ToString() on the byte array, which just defaults to returning the class name (system.byte[]) - which you then convert to a byte array. It should just be cast right away