Syntax 6: For opening an OLE storage member into a storage – PB Docs 2017

Syntax 6: For opening an OLE storage member into a
storage

Description

Opens a member of an open OLE storage and loads it into another
OLE storage object in memory.

Applies to

OLE storage objects

Syntax

olestorage.Open ( substoragename, readmode, sharemode, sourcestorage )

1	olestorage.Open ( substoragename, readmode, sharemode, sourcestorage )

Argument	Description
olestorage	The name of a object variable of type OLEStorage into which you want to load the OLE object.
substoragename	A string specifying the name of the storage member within sourcestorage that you want to open. Note the reversed order of the sourcestorage and substoragename arguments from Syntax 4.
readmode	A value of the enumerated datatype stgReadMode that specifies the type of access you want for substoragename. Values are: stgReadWrite! — Read/write access. If the member does not exist, Open creates it. stgRead! — Read-only access. You cannot change substoragename. stgWrite! — Write access. You can rewrite substoragename but not read its current contents. If the member does not exist, Open creates it.
sharemode	A value of the enumerated datatype stgShareMode that specifies how other attempts, by your own or other applications, to open substoragename will fare. Values are: stgExclusive! — (Default) No other attempt to open substoragename will succeed. stgDenyNone! — Any other attempt to open substoragename will succeed. stgDenyRead! — Other attempts to open substoragename for reading will fail. stgDenyWrite — Other attempts to open substoragename for writing will fail.
sourcestorage	An open OLEStorage object containing substoragename.

Return value

Return value

Integer.

Returns 0 if it succeeds and one of the following negative values
if an error occurs:

-2 — The parent storage is not open

-3 — The member is not found (when opened for reading)

-9 — Other error

If any argument’s value is null, Open returns null.

Usage

An OLE storage file is structured like a directory. Each OLE
object can contain other OLE objects (substorages) and other data
(streams). You can open the members of an OLE storage belonging to a
server application if you know the structure of the storage. However,
PowerBuilder’s functions for manipulating storages are provided so that
you can build your own storage files for organizing the OLE objects used
in your applications.

The whole file can be an OLE object and substorages within the
file can also be OLE objects. More frequently, the structure for a
storage file you create is a root level that is not an OLE object but
contains independent OLE objects as substorages. Any level in the
storage hierarchy can contain OLE objects or be simply a repository for
another level of substorages.

Opening nested objects

Because you can specify path information within an OLE storage
with a backslash as the separator, you can open a deeply nested object
with a single call to Open. However, there is no error checking for
the path you specify and if the Open fails, you will not know why. It
is strongly recommended that you open each object in the path until
you get to the one you want.

Examples

This example opens the object in the file MYSTUFF.OLE and loads it
into the OLEStorage variable stg_stuff, as in the previous example. Then
it opens the substorage drawing_1 into a second storage variable. This
example does not include code to close and destroy any of the objects
that were opened.

integer result
OLEStorage stg_stuff, stg_drawing
 
stg_stuff = CREATE OLEStorage
result = stg_stuff.Open("c:ole2mystuff.ole")
IF result &gt;= 0 THEN
      stg_drawing = CREATE OLEStorage
      result = opest_drawing.Open("drawing_1", &amp;
         stgRead!, stgDenyNone!, stg_stuff)
END IF

integer result

OLEStorage stg_stuff, stg_drawing

stg_stuff = CREATE OLEStorage

result = stg_stuff.Open("c:ole2mystuff.ole")

IF result >= 0 THEN

stg_drawing = CREATE OLEStorage

result = opest_drawing.Open("drawing_1", &

stgRead!, stgDenyNone!, stg_stuff)

END IF

See also

Save

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Powerbuilder Documentation 2017

August 20, 2023

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