The Media Center Sandbox

Has anyone figured out how to invoke the shiny new photowall slideshow in Windows 7 from within a plug-in?

I can get the standard slideshow up okay with NavigateToPage / PageId.Slideshow, and pass in the path to my preferred slideshow folder, but I'd like to be able to display the photo wall.

(The photowall is the one that appears by default under Photos & Videos -> Favourites on the start menu, where the display pans around and zooms in & out of an entire wall filled with photos.)

Thanks,

Eddy

eddyc:

Has anyone figured out how to invoke the shiny new photowall slideshow in Windows 7 from within a plug-in? I can get the standard slideshow up okay with NavigateToPage / PageId.Slideshow, and pass in the path to my preferred slideshow folder, but I'd like to be able to display the photo wall. (The photowall is the one that appears by default under Photos & Videos -> Favourites on the start menu, where the display pans around and zooms in & out of an entire wall filled with photos.) Thanks, Eddy

There is no way to invoke that programmatically.

If you really want to, you can try the screensaver interface for the windows screensaver but you have to make sure that media center is in full screen and setup the media center picture screensaver settings through the registry, to have the picture wall auto launch.

Alternatively, navigate to start menu, then do a default action (through IAccessible interface) on the "Play All" button under the Pictures strip.

Yes I admit these methods are not pretty.

---

This posting is provided "AS IS" with no warranties, and confers no rights.

David Teo
SDET
Microsoft Corporation

Thanks for the follow-up David. I hadn't considered using iAccessible, but this might be a fairly robust approach that will sort out one or two other problems for me too. I'll give it a try.

(Obviously, it would be nice to have a more direct way to get to the Photowall, so hopefully it's now on the wishlist for Windows 8...)

Eddy

For the benefit of anyone else following this thread, I ended up going with the ScreenSaver approach, which is working fine. It relies on the screensaver not being disabled, but that's okay for my application.

I had trouble getting IAccessible to work, and there is some discussion in other forums about stability issues when accessing it from C#, so it seemed like more work than the end result would justify.

Here's the code snippet I'm using to invoke the wall:

[DllImport("User32.dll")]
public static extern int SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

[DllImport("User32.dll")]
public static extern int PostMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

const int WM_SYSCOMMAND = 0x0112,
const int SC_MAXIMIZE = 0xF030
const int SC_SCREENSAVE = 0xF140;
const int HWND_BROADCAST = 0xFFFF

Process[] localByName = Process.GetProcessesByName("ehshell");

// Make Media Center fullscreen (does nothing if already full screen)
SendMessage(localByName[0].MainWindowHandle, WM_SYSCOMMAND, (IntPtr)SC_MAXIMIZE, (IntPtr)0);

// Invoke screen saver
PostMessage(new IntPtr((int)SpecialHandles.HWND_BROADCAST), WM_SYSCOMMAND, (IntPtr)SC_SCREENSAVE, (IntPtr)0);

I just noticed that Microsoft.MediaCenter.UI.Accessibility has a public IAccessible class, which seems to be a C# mapping onto the usual IAccessible stuff. It's not documented in the SDK, however.

Has anyone played with this? If it provides a more straightforward interface to the IAccessible information within Media Center, it would be very helpful indeed.