Controlling caching of BitMapImage under WinRT

By default Bitmap Images are cached by WinRT with no intervention required by the developer.  Often times this is a good thing but there are some occasions where this is undesirable.  Although there doesn’t appear to be any obvious control in the API reference I have found that adding a dummy querystring to the BitMapImage source filename reference does the trick and also can offer precise control over the length of caching required (if any) .

Here is how I currently manage caching in a project and limit it to being refreshed once every hour:

In My App.Config I set up a static variable:

public static String CacheOffset = "?Cache=" + ;
System.DateTime.Now.DayOfYear.ToString() + ;
System.DateTime.Now.Hour.ToString();

When I populate my local collection I then use something like:

String MyImagePath=”MyBitMapImage.png”+App.CacheOffset;

This way the images are cached for the duration of the users WinRT session and also up to an hour beyond the initial population of my data collection.   Obviously I can vary this duration using different parameters from the current system date and time.  For instance the following would ensure that effectively no caching is carried out between user sessions:

public static String CacheOffset = "?Cache=" + ; System.DateTime.Now.Ticks.ToString() ;

If you wanted to update the image during a session then it would simply be a case of populating your image source using a different ‘virtual cache’ value for CacheOffset.

I suspect there may be better ways to achieve the same objective but for now this works for me.

Live Tile Browser – Windows 8 Certification!

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Following a gruelling (OK, not really that gruelling) 2 days in the Labs at Microsoft a couple of weeks ago am happy to say that “Live Tile Browser” has received certification for submission to the Windows 8 store.  (I understand that this is one of the first, if not the very first app in the UK to do so!)

I received some great feedback as a result of my time in the labs, much of which has been put to use in developing improvements to the App itself. 

Live Tile Browser should be available with the next iteration of Windows 8 (release candidate) some time next month!

There are still a couple of surprises held back for the App’s release and a video is needed to do justice to the smooth animation but for now here are a few screenshots of the current build:

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Live Tile News – Download Stats

“Live Tile News” had a very favourable review on the BBC’s technology program “Click” last week and I have had a lot of questions around the impact on downloads.

The first chart shows downloads for April – with the healthy spike being a result of the coverage received.

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The second chart is specific to “Live Tile News” and shows the more dramatic spike in interest as a result of the show.

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The vast majority of downloads were, as might be expected, in the UK but as this App supports US and Global news it will be interesting to monitor if there is any knock on effect in these territories going forward.

Ian

NB The review can be viewed on my earlier blog post here


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NB All developer proceeds from sales and advertising of this App go to charity