Question

This is a variation on a question that has been asked here several times. One example: Display an image contained in a byte[] with ASP.Net MVC3. The question is how to render an image from a byte array.

In all those questions, there is an Action similar to one of the answers in the link I provided above:

public FileContentResult Display(string id) {   
byte[] byteArray = GetImageFromDB(id);   
return new FileContentResult(byteArray, "image/jpeg");
}

With an image tag similar to this:

<img src="@Url.Action("Display", new { id = Model.Id })" />

This is done because it’s not possible to send a byte array through a GET request, so just the id is sent allowing a lookup in the Action method. I get this part, it’s not the problem. What I’m trying to do is create a ‘Preview’ page, where they can check their work before saving in the database. They can see the layout of the Title, Text and Image and decide whether to save, or go back and Edit some more. Therefore, the ‘GetImageFromDB(id)’ part won’t work, since the object has not been saved yet to the database.

Is there any way to accomplish this, or do I just have to save the byte array temporarily in the database and access it that way for the Preview page?

Answer 1

You need to store the uploaded file somewhere on the server if you want to show it later (as a preview or full size image). Whether it is the database or the file system it is up to you. So once the file is uploaded you could store it as a temporary file on some location on the server by renaming it using some unique Guid and return this Guid to the client so that it can create an action link to a preview controller action passing the Guid which will fetch the file from the temporary location and stream it to the client.