文件下载/在线预览图片

//在线图片下载
 WebRequest myrequest = WebRequest.Create("https://***/share/share.jpg");
WebResponse myresponse = myrequest.GetResponse();
Stream imgstream = myresponse.GetResponseStream();
Image img = Image.FromStream(imgstream);
MemoryStream ms = new MemoryStream();
img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
return File(ms.ToArray(), "image/png", "EDM_大会.png");

//图片在线查看

           
   private readonly IHostingEnvironment _hostingEnvironment;
    public rController( IHostingEnvironment hostingEnvironment)
     {
            _hostingEnvironment = hostingEnvironment;
    }
public async Task<ActionResult> p(string tc,string t)
{
        string webRootPath = _hostingEnvironment.WebRootPath;
            using (var sw = new FileStream(webRootPath + "/img/share.jpg", FileMode.Open))
            {
                var bytes = new byte[sw.Length];
                sw.Read(bytes, 0, bytes.Length);
                sw.Close();
                return new FileContentResult(bytes, "image/jpeg");
            }
}