There's no substitute for customer feedback! [Improving Windows Phone 7 application performance now a bit easier with LowProfileImageLoader and DeferredLoadListBox updates]

re: There's no substitute for customer feedback! [Improving Windows Phone 7 application performance now a bit easier with LowProfileImageLoader and DeferredLoadListBox updates]

David Anson — Tue, 15 Jan 2013 18:11:28 GMT

Pete,

Sure, that's a neat idea. Shawn Burke actually wrote a framework for that called AgFx: github.com/.../AgFx. You may want to check that out; my understanding is that it supports exactly the scenario you're interested in.

Good luck!

re: There's no substitute for customer feedback! [Improving Windows Phone 7 application performance now a bit easier with LowProfileImageLoader and DeferredLoadListBox updates]

Pete — Tue, 15 Jan 2013 08:31:17 GMT

Hi David,

great stuff! Wouldn't it be a good idea to have an option to store the downloaded file in isolated storage for later use? And then automatically check whether the icon is already available in isolated storage and load it from there instead of the internet?

re: There's no substitute for customer feedback! [Improving Windows Phone 7 application performance now a bit easier with LowProfileImageLoader and DeferredLoadListBox updates]

David Anson — Sun, 02 Sep 2012 06:27:43 GMT

iglaweb,

If there's a crash, you can usually find out what the exception was in the debugger and use that (plus the call stack) to figure out what went wrong. Sometimes it can help to turn on first chance exception handling in the debugg.r as well (a web search will say how to do that). Because my sample application works properly, I'm not sure offhand what would cause this - another thing to try would be incrementally commenting stuff out of your application until the problem goes away and using that to see what the specific cause might be.

Hope this helps!

re: There's no substitute for customer feedback! [Improving Windows Phone 7 application performance now a bit easier with LowProfileImageLoader and DeferredLoadListBox updates]

iglaweb — Fri, 31 Aug 2012 09:31:31 GMT

Hello!

Although I found issues, listbox perfomance with your LowProfileImageLoader class is very high (I use observable collection).

I try to use your LowProfileImageLoader class, but there is a issue. All is fine when I scroll listbox(or your DeferredLoadListBox) slow, but when I scroll very fast, the emulator crashes(but when I remove images from items all is good), there is no problem with your twitter example, but I can't understand what I'am doing wrong. I tried many times and different ways, but not result :( I download listbox items only per 20 and there is another small issue. Images sometimes are not refreshing immediately. Can you help me?

re: There's no substitute for customer feedback! [Improving Windows Phone 7 application performance now a bit easier with LowProfileImageLoader and DeferredLoadListBox updates]

David Anson — Wed, 25 Jul 2012 20:17:41 GMT

Geobert,

Please see the comments in this post for some information about ImageOpened: blogs.msdn.com/.../keep-a-low-profile-lowprofileimageloader-helps-the-windows-phone-7-ui-thread-stay-responsive-by-loading-images-in-the-background.aspx

But you may be able to modify the code for LowProfileImageLoader itself to get the effect you want by adding in an Animation of the Image's Opacity property from 0->1.

Hope this helps!

re: There's no substitute for customer feedback! [Improving Windows Phone 7 application performance now a bit easier with LowProfileImageLoader and DeferredLoadListBox updates]

Geobert — Wed, 25 Jul 2012 15:44:53 GMT

Thank you for this lib!

Is there a way to fade in the downloaded image? I tried from ImageOpened but I discover here that it is not triggered :(

Thanks for any help!

re: There's no substitute for customer feedback! [Improving Windows Phone 7 application performance now a bit easier with LowProfileImageLoader and DeferredLoadListBox updates]

David Anson — Tue, 19 Apr 2011 05:40:50 GMT

Veri,

1. You can definitely use LowProfileImageLoader with the default ListBox. The two classes work together, but are not *tied* together. :)

2. I don't quite understand the question, but if you're asking if you could make UriSource a string-typed property instead of a Uri-typed property, that should work just fine (once you update the parts of the code that assume Uri).

Hope this helps!

re: There's no substitute for customer feedback! [Improving Windows Phone 7 application performance now a bit easier with LowProfileImageLoader and DeferredLoadListBox updates]

Veri — Tue, 19 Apr 2011 01:50:54 GMT

Hi David,

I have tried your suggestion but it still didn't work :(

I have a few questions though:

1. Do I have to use the DeferredListBox or can I use the default ListBox?

2. Can I change the LowProfileImageLoader.UriSource to catch string instead of url?

Regards,

Veri

re: There's no substitute for customer feedback! [Improving Windows Phone 7 application performance now a bit easier with LowProfileImageLoader and DeferredLoadListBox updates]

David Anson — Fri, 08 Apr 2011 16:41:57 GMT

Veri,

Nothing about switching to a different ItemsPanel should affect how LowProfileImageLoader works. You might try switching back to the default ItemsPanel to see if the problem remains - if so, then it's probably something else (like a broken Binding?). Alternatively maybe try WrapPanel+LowProfileImageLoader outside a ListBox to verify that works okay.

re: There's no substitute for customer feedback! [Improving Windows Phone 7 application performance now a bit easier with LowProfileImageLoader and DeferredLoadListBox updates]

Veri — Fri, 08 Apr 2011 14:39:10 GMT

Hi David,

I have tried to use the LowProfileImageLoader in a ListBox and WrapPanel as the ListBox's ItemsPanel but my image was not loaded at all :(

Do you have any idea why?

Regards,

Veri