After figuring out how to make SQL Mobile work on my XP PC (I have VS 2005 installed so the license works), I decided to port to the desktop the device component DLL I use in all my products. Most of the code (like 99% of it) was immediately reused, barring the occasional precompiler tweaks. The major challenge was not to change too much on the support code and this implied simulating a RAPI or TCP/IP connection and the corresponding data streams.
The solution I came to was quite simple: two asynchronous data buffers. The first is written to by the client code (dssce.dll) and read by the server (LocSqlCe.dll). The second data buffer is used in the exact reverse way.
When I finally managed to make the whole thing work I was amazed by how slow it was... The data streaming code was the culprit because it was chewing up too much CPU bandwidth in its own thread, especially while waiting. The solution? A criteriously inserted Sleep(0) on the reader thread.
The bottom line is that DesktopSqlCe users may now develop their applications against a local SQL Mobile database. Look Ma: no PDA!
Adventures in Desktop App Conversion
1 week ago