Understanding the DLL Header File
Notice that LaunchViewer() includes but a single call: CreateProcess(). To my way of thinking, this bit of logic epitomizes the elegance of CE's remote procedure call functionality. While there are very strict limitations on how you can invoke a function, the function you invoke is virtually unlimited in its capability because it can in turn create processes. In a nutshell, the whole device is your oyster once you successfully invoke the first function.
Here are the parameters to CreateProcess():
BOOL CreateProcess( LPCTSTR lpApplicationName, LPTSTR lpCommandLine, LPSECURITY_ATTRIBUTES lpProcessAttributes, LPSECURITY_ATTRIBUTES lpThreadAttributes, BOOL bInheritHandles, DWORD dwCreationFlags, LPVOID lpEnvironment, LPCTSTR lpCurrentDirectory, LPSTARTUPINFO lpStartupInfo, LPPROCESS_INFORMATION lpProcessInformation );
Notice that like CeRapiInvoke(), CreateProcess() provides a means by which to pass data to the function being invoked (via a command line). By using these functions in concert, you create a fundamentally unlimited integration of the CE and desktop Windows worlds.
Download the source code file for this article here.
In the next lesson, you'll complete this application system by creating an HTML viewer control on the CE device. Once animated, this control allows you to pass any data that is capable of being rendered using HTML tags from the desktop device to the CE device. The power and elegance of this approach can hardly be overstated. Not only does it provide enormous flexibility, it largely insulates the application designer from the vagaries of various CE platforms.
About the Author
Nancy Nicolaisen is a software engineer who has designed and implemented highly modular Windows CE products that include features such as full remote diagnostics, CE-side data compression, dynamically constructed user interface, automatic screen size detection, and entry time data validation.
In addition to writing for Developer.com, she has written several books, including Making Win 32 Applications Mobile.
# # #
Page 2 of 2