Inelegant method: sendkey {tab} til arrive in field, then sendkey {"^c"} to grab the contents.
Elegant method == ?
It depends a lot on what you mean by 'windows app', the underlying nature of the 'field', and which version of Windows you are using. However, to start you may want to check out the Roboscripter utility. It can be found in the WinBatch folder of your start menu. It helps you write Control Manager extender based scripts. It also helps you to determine whether or not the Control Manager extender can be used to obtain the information you seek.
It's an old "legacy" app, running on Win7 or Server 2008R2. Please see video at:
http://screencast.com/t/uk4EIlqs
Thanks,
Steven
Looking at a video will not offer much in the way of information. Check out Roboscripter.
I have roboscripter at the ready... how shall I use it?
(I show a clumsy attempt to use it in that video.)
Read the documentation in the help file: Condolidated WIL->Wil Extenders->Control Manger Extender->Roboscripter. It isn't that hard to figure out.