Windows Phone 7 - Hello World!

Ever since Nokia announced its partnership with Microsoft and made Windows Phone 7 its primary smartphone operating system, I anxiously wanted to give it a spin. So in this post, I am going to start by setting up a development environment for Windows Phone 7 followed by a simple Hello World example.

Windows Phone 7 is primarily a successor of the Windows Mobile Platform (the last one in the line being Windows Mobile 6.5). It's a major revamp in Microsoft's Mobile strategy in terms of its application development model.

Windows Phone 7 no longer supports unmanaged code (Win32 and C++ are gone). It is purely built on Managed Code covering Silverlight, XNA and the .NET Framework (Programming Languages include C# and VB.Net). Here's a nice article on Windows Phone 7 application development model - http://blogs.msdn.com/b/abhinaba/archive/2010/03/13/windows-phone-7-series-programming-model.aspx.

To get started with Windows Phone 7 development, download the Windows Phone Developer Tools RTW (Release To Web). It includes the following tools -

1. Visual Studio 2010 Express for Windows Phone
2. Windows Phone Emulator Resources
3. Silverlight 4 Tools for Visual Studio
4. XNA Game Studio 4.0
5. Microsoft Expression Blend for Windows Phone

If you are already using a higher version of Visual Studio or Expression Studio, this toolkit will install extensions to the existing IDEs. The release is also available as an .iso image. Though the Windows Phone 7 toolkit comes equipped with Expression Blend, for most of the basic applications the design mode of Visual Studio should be sufficient.

To get a hands-on experience with Windows Phone 7, let's take a simple application which accepts a username and greets him/her in the next page. The best part of Windows Phone 7 development is that it is pretty much in the lines of other Visual Studio project types we are familiar with like the Windows Forms Applications, WPF Applications and ASP.Net Applications where in the UI can be created easily using the designer and the business logic is maintained in a code beside event driven model in another .cs or .vb file depending on the programming language.

As already mentioned, Windows Phone 7 is built on Silverlight and thereby every screen has a corresponding XAML (eXtensible Markup Language) page, each having its own code file. Movement between these XAML pages is made possible through an instance of a NavigationService class for every page.

There are three important methods provided by NavigationService - Navigate, GoForward and GoBack. Navigate takes a Uri instance specifying the URI location and loads the XAML page specified.

NavigationService.Navigate(new Uri("/NamePage.xaml", UriKind.Relative));

GoBack and GoForward loads the previous and next pages respectively.

NavigationService.GoBack();
NavigationService..GoForward();

Parameters can be passed across XAML pages by appending them to the URL and retrieving them using the QueryString property of the NavigationContext object. This concept of Windows Phone 7 was very surprising. Since Mobile Applications are very similar to Windows Applications, passing parameters through URLs like Web Applications looked a bit off-track.

NavigationService.Navigate(new Uri("/NamePage.xaml?name=" + name, UriKind.Relative));
string name = NavigationContext.QueryString["name"];

Download the example code here.