WP7 Application Settings on IsolatedStorage

I'm starting to put together pieces for my WP7 application and one of the features I needed is to save/load application settings. There is already an integrated mechanism using IsolatedStorageSettings.ApplicationSettings, but I've implemented it using an XML file located on the IsolatedStorage. The main reason why I don't use the default one is because I want to upload/backup the file to DropBox or SkyDrive making it possible to share the same settings between various versions of the same application running on different platforms (in my case iOS and WP7) and also the user can restore the settings of an application when he changes the phone or reinstalls the application.

The VS2010 solution I am posting at the end of this entry is structured in 3 projects:

1. ConfigManager is the library used for settings management. It can read/write the settings. It also implements an indexed property, but as WP7 v1 uses Silverlight 3 it's not possible to use bindind to indexed properties (this feature is only available from Silverlight 4). If you want to directly bind settings to UI elements you will have to create bind-able properties . If the configuration file is not found on the IsolatedStorage the library will try to restore the file from Content (have a look at the sample TestConfig). It is possible to manually add values to the settings. There is nothing extraordinary in the source code.

2. TestConfig is a sample project that uses the library ConfigManager. It has a default configuration file deployed in Content (settings.xml). One of the things to pay attention to if you are binding to textboxes is to be sure that the binding is updated before saving the settings (this because if a textbox has focus, you modify it's value and select save settings you will loose the modifications if the binding is not updated). This is why I force the update of the source on TextChanged event:

((TextBox)sender).GetBindingExpression(TextBox.TextProperty).UpdateSource();

not a very elegant solution but it's the only one I found till now.

3. TestConfigMVVM is the same test project using MVVM light library. I did not include a settings file in the content and I load the default values manually.

Hope you will find the library useful and that you could spare the time I've spent in developing this part. The next post will be on synchronization with DropBox.

AppSettings.ZIP

NAMASTE

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WP7 SqliteClient Preview

WP7 developer devices are already out in the US and I still hope I will qualify for one here in Italy. I would really love to test one. Brandon PLEASE don't forget me :)

As my proposal was a better port of the Sqlite engine I did some optimizing on the engine and also implemented/adapted a SqliteClient that is easier to use than normal sqlite3 commands.

At the "engine" part I use the journal file persistent this way the engine doesn't delete and create the journal at each command. I've also eliminated SQLITE_DEBUG from conditional compilation symbols spares some temporary file access.

For the client at the beginning I've wanted to compile the System.Data and Sqlite class from Monotouch, but after looking a little bit at the source code I've realized that there are tons of things that doesn't make sense on WP7. I wanted to keep it simple and searching I've found the SqliteClient.cs written by Frank Krueger for Monotouch. I've adapted the class to run with our library and got a pretty nice result.

I've also improved the test project and now you are able to set how many rows will be inserted, select the inserted rows and see the elapsed times for insert/select commands. For the insert I've tested two methods: the first with prepare, step, finalize and the second one with sqlite3_exec (which should be the same) and the insert time are more or less the same.

Anyway it's only a preview as it was not intensively tested and because it can be improved. If some of you find ways to optimize the library please let me know and I will post it for everybody. Also let me know what you think.

Here you have the link to the source code

NAMASTE

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WP7 IsolatedStorage speed improvement

If you remember some time ago I did some tests on the IsolatedStorage and the speed was not very impressive (it was 127 slower than the FileStream). In the new beta version there is a TREMENDOUS improvement. I rerun the old test in the new emulator and these are the results:

Dividing the two values 0.0632/1.1866=0.0532 which is almost the same with FileStream. At this point it does make sense implementing/porting a database engine on IsolatedStorage. Well done WP 7 Team on this aspect.

NAMASTE

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WP7 IsolatedStorage Backup/Restore

One of the drawbacks of the WP7 Emulator is that it doesn't save the state between sessions and also it is difficult to deploy a file with your project and then use it. This means that every time you start a new session of the emulator you loose all the data on the IsolatedStorage.
I've developed a small solution (there is room for improvement) for backing-up and restoring the files (folder structure included) of the IsolatedStorage. It is using an WCF service that stores/sends file content from/to the IsolatedStorage in/from a folder named Backup located in the WCF project folder. For optimizing the communication the service uses binaryMessageEncoding. It also splits the files in 100Kbytes parts (you can modify this size from the source code if you want bigger parts- it will be faster) .
The solution is easy to use even if it took me a lot of time to make it work (especially the readerQuotas, maxBufferSize, maxStringContentLength). In fact I was having "fun" with it at 3 o'clock in the morning. If you want to backup your IsolatedStorage just hit backup and it will write the content of IsolateStorage in the Backup folder of the pc. If you want to restore/copy files to the IsolatedStorage copy the files/folders you want to the Backup folder of the PC and then hit Restore and it will copy all the data to the IsolatedStorage.

Hope you'll like it! Don't forget to modify the ServiceReferences.ClientConfig before you run the project

As usual you can download the Source code

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WP7 IsolatedStorage Speed

I was wondering if it makes any sense fully implementing SQLite on IsolatedStorage as the "quality" of the db support will depend a lot on the speed of of the storage. I read on some posts that the speed of IsolatedStorage was a problem, but I've wanted to compare it with the speed of the Filestream. The problem is that you cannot compare the two directly so I had the idea to compare both of them with another "item" that is available on both systems. I've chosen a MemoryStream test as a constant. I am not making the same test between MemoryStream and IsolatedStorage or between MemoryStream and FileStream as I am not interested on how much faster is MemoryStream (that's why on the real device FileStream seems faster then MemoryStream but it's not true as it is not the same amount of data). I run the test for 10 times and then make an average (to have a more precise result)

Dividing IsolatedStorage/MemoryStreamSpeed=8.5991/1.2251=7.019 and FileStream/MemoryStream= 0.7/12.7=0.05511. To get an idea about the speed differences we devide the two results and we get 127.3634 which means that the IsolatedStorage is 127 times slower than FileStream. Of course this is not an exact result, but should reflect the speed difference. I might have some "glitches" in the tests but I cannot figure them out. If this result is at least near to the real one it doesn't make any sense to implement db engine on IsolatedStorage.

Another thing that I've noticed is that the x86 implementation of WP7 Emulator is much faster then the ARM emulation of 6.5 Emulator (at least MemoryStream implementation).

You can download the projects here

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