Rapid proto-typing (03 Mar 2006)

Much to my dismay, I found myself in a situation where the following hack is useful. I shudder at the thought of actually using it because of its inherent instability, but sometimes it's better than a poke in the eye with C#.

If you're automating an application which, while executing a command, may pop up error or warning messages and wait for user input, you may need to explicitly send a keystroke to that application. Fortunately, this is reasonably simple using cscript.exe, the WSH Shell object and VBscript:

Set WshShell = WScript.CreateObject("WScript.Shell")
WshShell.AppActivate ("Appname as it appears in the main window title")
WshShell.SendKeys "{ENTER}"

While testing this, I learnt that the application name parameter to AppActivate can actually be an abbreviation. For instance, if you run Word, its main window title is usually something like "gazonk.doc - Microsoft Word". AppActivate actually uses a simple best-match algorithm so that the following will still work as expected:

Set WshShell = WScript.CreateObject("WScript.Shell")
WshShell.AppActivate ("Microsoft Word")
WshShell.SendKeys "foo"

The SendKeys method turns out to be pretty convenient since it allows to describe non-printable characters with a special notation, such as {BREAK} for the Break key, {PGUP} and {PGDN} for moving pagewise, {DEL}, {HOME}, all the function keys et cetera.

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