Q: Use the System's File
Properties Dialog
My application offers a display of filenames as part of its user
interface. I'd like to give users the ability to bring up the system
File Properties dialog as one of the options when they right-click on a
filename. How can I do that?
A:
This task involves only a single quick call to the ShellExecuteEx API
(see Listing 1).
Unlike ShellExecute, ShellExecuteEx enables you to call any context menu
item related to a given shell object—"properties," in this
case.
Set up the call by creating a SHELLEXECUTEINFO structure and filling
its first element (cbSize) with the structure's overall size so the
system knows that you know what you're doing. Create the flag mask by
combining the constant values for SEE_MASK_INVOKEIDLIST (which allows
the use of shortcut menu extension verbs, rather than only Registry
verbs), SEE_MASK_FLAG_NO_UI (which prevents the system from popping
message boxes on errors), and SEE_MASK_DOENVSUBST (which expands
environment variables in the passed filespec).
It's good form to stuff the structure's hWnd element with the handle
of a window in your app. This window serves as the parent of any
error-related message boxes the system pops up, although you've
instructed the system already not to do this. The lpVerb element is the
key to bringing up the desired dialog—assign "properties" to
this element. Finally, assign the desired filename to the lpFile
element, and make the call to ShellExecuteEx.
You can gauge your call's success by examining the SHELLEXECUTEINFO
structure's hInstApp element for a value greater than 32. Values less
than 32 indicate an error occurred, and you can interpret the exact
cause from the specific value. —K.E.P.
About the Author
Karl E. Peterson is a GIS analyst with a regional transportation
planning agency and serves as a member of the VSM
Editorial Advisory Board. Online, he's a Microsoft MVP and a
section leader on several DevX forums. Find more of Karl's VB
samples at www.mvps.org/vb.
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