Here is version 1 of my countdown Vista gadget for the MIX essentials event on April 24th in Belgium. It's a very simple gadget but since I found one for the MIX08 event in March I also wanted for our own event. Download gadget link to my SkyDrive is below.
The gadget is developed in Silverlight 1.0, which allows me to add a small animation easier that doing this in HTML. As this was the first time I built a Vista sidebar gadget I looked up some info on how to create gadgets. I'm posting the main resources I used to get it to work:
I first developed the application as a normal Silverlight 1 application using Expression Blend 2.5 (March 2008 preview) and Visual Studio 2008. After getting it to work normally in the browser I started adding the required changes to transform it into a Windows Vista sidebar gadget:
1. Added a gadget.xml file to the project. See the definition of such a file in the MSDN documentation.
Set the isWindowsless property to true (this allows for moving and closing the gadget in the sidebar, as well as a transparent background). Set the background property to transparent. Because I have slightly rounded edges and want the normal sidebar or application background to come through.
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3. Added a function for debug information, as describes here in the MSDN documentation. I've also used DebugView which works really well.
After testing my Silverlight application normally I decided it was time to test it on the sidebar. All gadget required settings were made, the archive file (zip renamed to gadget) and then: nothing was working on the sidebar. It seemed my onLoad event was no longer being called, actually there was no error message at all.
As I had another gadget on the machine that was also using Silverlight 1 I decided to reactivate that one and check what the difference was. Now this one was no longer running either. Problem must be with Silverlight 2 beta 1 installed. Tried it on a machine without the beta and it was working correctly.
Apparently there seems to be an issue with Silverlight 1 gadgets no longer working once you have the Silverlight 2 beta installed. Fortunately there is an easy fix for this (thanks Stefan). In the HTML page initializing the Silverlight control you need to add x-gadget:/// syntax before the name of the xaml file.
Adding that solved the issue, the gadget now works both on machines with Silverlight 1 or Silverlight 2 beta 1 runtimes.
What's next: hopefully a version 1.1 with some very sleek look if I find a designer/devigner to give me a hand :-)