Last post Jan 01, 2008 02:15 AM by Near
Dec 12, 2007 09:35 AM|powercrazy|LINK
I have a web application in which I dynamically generate an image from a number of composite images. To achieve this, I have an ImageMap control that invokes its 'ResolveURL' method. The parameter of the message is the URL of a HTTPHandler which then
delegates to another method that dynamically generates the appropriate image and returns the result as a memory stream to the ResolveURL call. This all works great when I load or refresh the page.
My problem is that I now want to do some additional manipulation that will allow a person to click on various different areas of the grid - depending on where they click, the image would change. I have used the AJAX UpdatePanel as a wrapper to the imagemap
so as to eliminate a full page refresh as we process clicks from the user. My problem is I can capture and process the click with no problems - I call the imagemap ResolveURL method as normal with the same URL of the HTTPHandler but the HTTPHandler never gets
invoked and therefore the image never changes. I.e. the HTTPHandler works perfectly and regenerates the image when the page is first loaded and during subsequent full page refreshes, but will not get invoked if the update was caused by an action within the
Any advice or suggestions you guys could give here would be much appreciated!
Dec 25, 2007 09:25 PM|Near|LINK
I have same problem with you. My ashx can not load when do postback with update panel. I make a trick by including my ashx in iframe. It's work. but I don't know why? Why an ashx cannot be loaded when callback?
Dec 28, 2007 06:22 AM|rxwen|LINK
I think it's because the image is cached on client side. Maybe you can try adding a random value at the end of the url of the handler as a querystring, so that it will be considered to be a different one each time.
Dec 28, 2007 09:58 PM|Near|LINK
Hum...I combine an ashx in multi view but it didn't work too. View 1 is ordinary form, and in View 2 I attach ashx. When Update Panel's postback, I change View 1 to View 2. But my ashx didn't load...
Dec 29, 2007 01:05 AM|rxwen|LINK
Can you be more specific about the logic of your code?
Will it be hit if a break point is set in the .ashx file?
Jan 01, 2008 02:15 AM|Near|LINK
No, It's not being hit by debugger. Strange. but if using postback, it will do