<br />The figure following shows what the code should look like including the lines of code associated with the click events of the �Clear all� and �Clear selected� buttons.<br /><br /> <img src="http://www.pocketpcthoughts.com/images/web/2003/sjostrom-may04-crossapp-new-05.jpg" /><br /><i>Figure 5: Behind the Scenes.</i><br /><br />We are now all set! That's it! In essence, our application requires only four lines of code. You can now test the application by simply clicking the �Start� button in the development environment. The application is loaded into an emulation environment that runs on your PC and can emulate all of the mentioned platforms. This means that you don�t necessarily have to have devices running all target platforms. However, if you intend to do more serious work you will eventually have to test your code on a real device. The following figure illustrates the demonstration application running in a real Pocket PC vs. running in the emulation environment.<br /><br /> <img src="http://www.pocketpcthoughts.com/images/web/2003/sjostrom-may04-crossapp-new-06.jpg" /><br /><i>Figure 6: The Real Thing vs. the Emulator.</i><br /><br />We will now move the application to other platforms!<br /> <PAGEBREAK> <br /><span><b>My Mobile List for Palm, Nokia Series 60 and Sony Ericsson P800/P900</b></span><br />Follow these steps to make �My Mobile List� a true cross platform application!<br /><br />1. Create a new project in Visual Studio .NET 2003.<br /><br />2. Choose to target the Palm platform.<br /><br /><img src="http://www.pocketpcthoughts.com/images/web/2003/fig07.JPG" /><br /><i>Figure 7: Choose Palm OS (160x160).</i><br /><br />The new project and new form is created, again with the right size relative the chosen target platform.<br /><br />3. Copy the controls from the Pocket PC project and paste them into the new Palm project. Since the Pocket PC and Palm platforms are different in resolution you will have to move the controls around a bit to make it all fit.<br /><br /><img src="http://www.pocketpcthoughts.com/images/web/2003/sjostrom-may04-crossapp-new-08.jpg" /> <br /><i>Figure 8: Designing the Palm user interface.</i><br /><br />4. Copy and paste the code behind the controls.<br /><br />5. Start the application!<br /><br /><img src="http://www.pocketpcthoughts.com/images/web/2003/fig09.JPG" /><br /><i>Figure 9: My Mobile List in the Palm emulator.</i><br /><br />Let�s move on and see how �My Mobile List� looks in Nokia Series 60 and Sony Ericsson P800/P900. The process of making these versions is identical to how the Palm version was made. Just follow the same steps but choose Nokia Series 60 and Sony Ericsson P800/P900 instead.<br /><br /><img src="http://www.pocketpcthoughts.com/images/web/2003/fig10.JPG" /><br /><i>Figure 10: My Mobile List in the Nokia Series 60 emulator.</i><br /><br /><img src="http://www.pocketpcthoughts.com/images/web/2003/fig11.JPG" /><br /><i>Figure 11: My Mobile List in the Sony Ericsson P800/P900 emulator.</i><br /><br /><span><b>Conclusion</b></span><br />Four lines of code makes one application run on four different platforms! I realize that the application isn�t the prettiest or feature rich and that I have cut some corners in regards to design guidelines which vary from platform to platform. But I do hope that this brief tutorial inspires you to dust off your programming skills and get busy writing some cool mobile applications. Good luck!