Robert Meek wrote: > Please bear with me as this is an area I have little or no knowledge > in. I understand you need to check for the particular key in the OnKeyDown > event, but I was assuming in error that the "and $80)> 0 was doing the same.
Sorry, it should actually be $8000; GetKeyState returns a Word, not a Byte. > How exactly does this part work? You say it masks out the other > bits in the byte returned by GetKeyState, but why is that necessary in this > example when it wasn't in the other I mentioned earlier where I had > originally been using GetAsynchKeyState? That now works perfectly without > having to mask out the other bits. The documentation says that the high-order bit represents whether the key is down. The low-order bit tells whether a togglable key is toggled. The documentation doesn't say anything about the 14 remaining bits, so you can't assume what their values will be. Since we're only interested in the value of bit 15, mask out the rest. Whenever you see anyone mention an API function, the *first* thing you should do to learn more about it is to read the documentation on MSDN. And not just the one-sentence blurb at the top. Read the whole thing, including the descriptions of the parameters and the return value, and especially the "remarks" section, if there is one, since that will usually include notes on when it is appropriate to use a function in preference over some other function, on where certain parameter values are supposed to come from, on what the function's inverse is, and sometimes on what the rest of the OS does in response to a call to that function. And note that the Win32 help that comes with Delphi is *not* a substitute for MSDN. If you have a convenient Internet connection, just bookmark the site. If you don't have the luxury of being online while you program, then download a copy or order it on DVD. The MSDN library is indispensable for anyone writing programs for Windows. -- Rob _______________________________________________ Delphi mailing list -> [email protected] http://www.elists.org/mailman/listinfo/delphi
