Question

I have a dropdown, that contains some list of StudentCode…
when user select any studentcode student data should be displayed in form with student’s Image…

for displaying Student Image, Im putting student image in cache memory… and I have one Iframe that gets the byte data from cache memory and render that image on my page… problem is… this thing need at least 1 postback…

can I make some partial postback to render this image?

Answer 1

I see couple problems with the implementation.

1) You should avoid using IFrames in general as there are better ways of handling rendering parts of the webpage.

2) Storing images in cache means that you actually downloaded all of them for each Student in the dropdown list and placed them in the cache. What if there are 100 students? Getting images for all of them and storing them might take a lot of resources.

I suggest you to do the autopostback on dropdown selected value change (via ajax call) which calls a method that will return a partial view with all the information you need for the particular student, including the image.

I found using Ajaxify library (http://max.jsrhost.com/ajaxify/) very easy and convenient for ajax calls.

You can do the same thing without ajax at all in which case the whole page will reload with the same result.