how to make a picture file downloadable? - asp.net

Question

I have an ASP.NET MVC3 application and I want to link_to an image file (png, jpeg, gif, etc), and when user clicks on it, the file goes to download, instead of the browser shows it; is there any way to do this?

Answer 1

take your link something like this:
#Html.ActionLink(
"Download Image", // text to show
"Download", // action name
["DownloadManager", // if need, controller]
new { filename = "my-image", fileext = "jpeg" } // file-name and extension
)
and action-method is here:
public FilePathResult Download(string filename, string fileext) {
var basePath = Server.MapPath("~/Contents/Images/");
var fullPath = System.IO.Path.Combine(
basePath, string.Concat(filename.Trim(), '.', fileext.Trim()));
var contentType = GetContentType(fileext);
// The file name to use in the file-download dialog box that is displayed in the browser.
var downloadName = "one-name-for-client-file." + fileext;
return File(fullPath, contentType, downloadName);
}
private string GetContentType(string fileext) {
switch (fileext) {
case "jpg":
case "jpe":
case "jpeg": return "image/jpeg";
case "png": return "image/x-png";
case "gif": return "image/gif";
default: throw new NotSupportedException();
}
}
UPDATE:
in fact, when a file is sending to a browser, this key/value will be generated in http-header:
Content-Disposition: attachment; filename=file-client-name.ext
which file-client-name.ext is the name.extension that you want the file save-as it on client system; for example, if you want to do this in ASP.NET (none mvc), you can create a HttpHandler, write the file-stream to Response, and just add the above key/value to the http-header:
Response.Headers.Add("Content-Disposition", "attachment; filename=" + "file-client-name.ext");
just this, enjoy :D

Answer 2

Well technically your browser is downloading it.
I don't think you can directly link to an image, and have the browser prompt to download.
You could try something where instead of linking directly to the image, you link to a page, which serves up the image in a zip file perhaps - which of course would prompt the download to occur.

Answer 3

Yes, you can.
Now, you'll need to customize this to suit your needs, but I created a FileController that returned files by an identifier (you can easily return by name).
public class FileController : Controller
{
public ActionResult Download(string name)
{
// check the existence of the filename, and load it in to memory
byte[] data = SomeFunctionToReadTheFile(name);
FileContentResult result = new FileContentResult(data, "image/jpg"); // or whatever it is
return result;
}
}
Now, how you read that file or where you get it from is up to you. I then created a route like this:
routes.MapRoute(null, "files/{name}", new { controller = "File", action = "Download"});
My database has a map of identifiers to files (it's actually more complex than this, but I am omitting that logic for brevity), I can write urls like:
"~/files/somefile"
And the relevant file is downloaded.

Answer 4

I don't think this is possible but a simple message saying right click to save image would suffice I think.