Windows – How to replace or customize Windows Mobile’s lock screen


How do I replace or customize standard Windows Mobile 6.1 lock screen to show my window with my program functionality?


Best Solution

If you mean the Device Lock screen, then you need to create a LASSD LAP dll to replace the inbuilt LAP dll.

I highly recommend reading and fully understanding the LAP Implementation Issues page and looking at the sample LAP dll in the Windows Mobile 6.0 SDK.

You will need to be privledged signed if you wish to work on Smart Phones (non-touch screen devices) or on some touch-screen devices from some operators. I would recommend getting it privledged signed if your a company.

There are some blog posts about LAP dll development that you may find useful (or not).

I have written a LAP dll myself so I know most of the issues involved (there are a lot).

Some problems I had:

  1. Some devices do not correctly supply SIP or T9 keyboard support that early in the boot process so it makes it hard to enter characters on some devices.
  2. Some touch-screen devices, the SIP button will not display (but still works) that early in the boot process.
  3. Supporting full device encryption is not easy. You have to support "logging" the user in correctly with no documentation on how to do it.
  4. Installing a LAP dll will drain battery on most devices. I haven't gotten to the bottom of this, but installing any LAP dll (even the Microsoft example) seems to cause the LAP dll to be polled calling VerifyUser all the time while the screen is off stopping the device from going into suspended state. This drains the battery very fast.