Testing out WP7 app at MS

I was lucky enough to work on a fairly high profile App for the US showcase launch, and lucky enough to get hold of one of the devices to try it out on before it went live! 🙂

WP7 device announcement on Monday

See article:
http://www.computerworld.com/s/article/9190140/Windows_Phone_7_to_launch_Monday_amid_crowded_smartphone_market

Also HTC’s 3D enhancements look pretty good:

Memory leak using Interaction Triggers on loaded event with MVVM light

Doing the following causes a memory leak and means the page that it appears on is not garbage collected:

<i:Interaction.Triggers>
<i:EventTrigger EventName="Loaded">
<ex:EventToCommand Command="{Binding LoadedCommand}" />
</i:EventTrigger>
</i:Interaction.Triggers>

I found this whilst doing some WP7 development, using the normal Loaded event does not cause an issue. It is detectable by calling GC.Collect() on the destination page and checking to see if the finlize of the previous page is called. I found the finalizer was called N times only when I quit the app (where N is the number of times I had navigated to the page).

Since the phone apps are torn down if they exceed 90MB it’s a bit more noticeable.

The Best WP7 app ever…

If I say so myself 😉 This is the actual WP7 Graphic.ly app – no demoware.

http://www.youtube.com/watch?v=1FtJ4iZajSw

WP7 low profile image loader

Great article on trickle loading images to keep UI responsive:

http://blogs.msdn.com/b/delay/archive/2010/09/02/keep-a-low-profile-lowprofileimageloader-helps-the-windows-phone-7-ui-thread-stay-responsive-by-loading-images-in-the-background.aspx

 

Pat Long added a workaround so that it works in blend at:

http://www.munkiisoft.com/blog/archive/2010/09/17/loading-external-images-in-the-background-ndash-windows-phone-7.aspx

 

Just need it to work with template binding now 😉

5 WP7 app previews

The one I’ve been working on is absent but this is quite interesting (given how hard it is to find real footage)…

http://www.iwantonly.com/watch/126249/

WP7 MonthYear Picker

For credit card expiry dates I needed to mod the Microsoft.Phone.Controls.DatePicker to only ask for Month and Year.

 

This was surprisingly convoluted but thanks for reflector, achievable. The xaml for the existing date picker is a resource in the dll but you do have to do a fair amount of work to keep it happy that it doesn’t have a day part anymore.

 

Seems to work and we’re on track for submitting the app tomorrow! 🙂

WP7 and loading images from IsolatedStorage

The code I inherited was loading an image into a MemoryStream then using this with BitmapImage.SetSource to load the image.

 

This completely bypasses a WP7 optimisation that speeds up loading images when SetSource is used directly with an IsolatedFileStream.

 

Check out:

http://timheuer.com/blog/archive/2010/09/16/windows-phone-7-developer-tips-and-tricks.aspx

WP7: Disabling sleep

Whack the following in App_Startup:

PhoneApplicationService.Current.UserIdleDetectionMode = IdleDetectionMode.Disabled;

Of course you should implement your own user idle detection. It would be nice if we could simply hook into a BeforeSleep event and stop it if we need to.

WP7: PNG not hardware accelerated but JPEGs are

http://www.anandtech.com/show/2969/windows-phone-7-series-the-anandtech-guide/13

 

And guess format my customer has all their product images in 😦