从当前HTML页面上传图像

Question

I have an image on my HMTL page. This is generated by DevExpress library at runtime and the src url points to a DevExpress script with a cache key:

<img id="Chart_89_IMG" src="/DXB.axd?DXCache=30f02093-de66-4ed6-8557-2382065c701a" />

I'm trying to get this file onto the server in a subsequent form post to use in an email. I've tried just passing the url in my form, but by the time it gets to the server, I get a 404 (assuming the cache key is expired).

I've also tried using canvas to get the bytes and pass that to the server, but was having trouble converting that byte stream back to an image, and canvas won't work for IE8, which I need to support.

My last idea was to include a file upload input on my form and pass the image to the server that way. But, how can I create a file from an image in javascript to use as an upload?

Any other ideas would be appreciated too!

Answer 1

Since this was DevExpress, I was able to change the BinaryStorageMode to the session:

settings.BinaryStorageMode = BinaryStorageMode.Session;

Then after I posted the form, the chart's bytes were accessible in the Session:

byte[] bytes = ((DevExpress.Web.ASPxClasses.BinaryStorageData)HttpContext.Current.Session[sessionKey]).Content;