Windows API: Item method implementation in OLE
2004-01-10 -- Michael Ware
Newsgroups: softvelocity.clarion.language
Jim,
Brilliant Thanks!! Using your tips I can now check the state of a service using:
! Check if the "Schedule" Service is running.
?ocxobject{prop:reportexception}=true
?ocxobject{prop:create}='WbemScripting.SWbemLocator'
objsvs=?ocxobject{'connectserver(,,,,,,,)'}
OBJSub = ?OcxObject{objsvs & '.GET(Win32_Service.Name=''Schedule'')'}
Message('service.NAME:' & ?OcxObject{OBJSub & '.NAME'})
Message('service.State:' & ?OcxObject{OBJSub & '.State'})
Message('service.Start Mode:' & ?OcxObject{OBJSub & '.StartMode'})
Message('service.Status:' & ?OcxObject{OBJSub & '.Status'} )
?ocxobject{prop:release}=OBJSub
?ocxobject{prop:release}=OBJsvs
But I've reached the end of my rope trying to implement calls to _newenum. The
following returns an IDispatch object into objEnum. But any attempt to access it
through the OLE control GPF.
objOS = (?OcxObject{objsvs & '.ExecQuery("Select * from Win32_QuickFixEngineering")'})
Message('OS=' & objOS) ! shows "`5474248"
BIND('IDispInterface',IDispInterface)
objEnum = ?OcxObject{objOS & '._newenum(&IDispINTERFACE)'}
objEnum[1] = '`' ! (replace chr(0) so this looks like a prop:object)
Message('Enum=' & objEnum) ! shows "`5474064"
BIND('objNxtArray',objNxtArray)
BIND('lNxtCount',lNxtCount)
objItem = ?OcxObject{objEnum & '.Next(1,&objNxtArray,&lNxtCount)'} !GPF
I suspect you had a good reason for using "a bit of assembler". . I'm going to
move on and try to get a "small" VB or VC exe that I can shell too to pull the data.
My targets here are the hot fixes (Win32_QuickFixEngineering) and OS data
(Win32_OperatingSystem).
Thanks again for the support. If anyone wants to FAQ the code for getting Service
data feel free.
-Mike
"jim kane" wrote in message
news:A921.1072838395.5597@discuss.softvelocity.com...
> I looked more closely at what you had done and looked back at some work on
> wmi I did a long, long time ago. I was very fortunate on that project as
> the network admin set everything up and wrote all the ldap queries.
>
> In any case the getobject is a com interface method. You're in essence
> trying to start in the middle of the story. The 1st step which your not
> doing is to use the wmi locator to connect to a wmi server. BTW the wmi
> services need to be running.
> The code to do that is:
> COUNT LONG
> objsvs cstring(20)
> objos cstring(20)
> CODE
>
>
> OPEN(MainWin)
> DISPLAY
> ACCEPT
> CASE EVENT()
> OF EVENT:OpenWindow
> ?ocxobject{prop:reportexception}=true
> ?ocxobject{prop:create}='WbemScripting.SWbemLocator'
> objsvs=?ocxobject{'connectserver(,,,,,,,)'}
>
> OF EVENT:Accepted
> CASE FIELD()
> OF ?Exit
> POST(EVENT:CloseWindow)
> OF ?GetOS
> objos = (?OcxObject{objsvs & '.ExecQuery("Select * from
> Win32_OperatingSystem")'})
> Message('ObjOS: '& objos)
> message(?ocxobject{objos & '.count'}) !displays '1'
> ?ocxobject{prop:release}=objos
>
> the next important thing is that you get OLE view and open the typelibary.
> it's in the same folder as the .dll and called WBEMDISP.TLB - if you search
> your hard drive you have it.
> if you open in in ole view and search for the execquery method you will find
> it returns a ISWbemObjectSet. As you pointed out earlier that object's item
> method is difficult to work with. The way arround that is the object has a
> _newenum method. VB supports that with the 'for each' syntax but clarion
> does not. You can write your own code to call via IDispatch to get the
> IEnum interface returned by _NEWENUM and use it's next method to loop thru
> all the objects in the set. I have never needed to do that because usually
> the objects provide their own explicit next method or the item method is
> easier to use. I did do it once back when I was first starting with come
> using a bit of assembler I published long ago in clairon mag but have neve
> had a need to update it so I cant really help you. If you are serious about
> wmi you'll need to attack that beast.
>
> the call to .get that followed does not return the same type of object and
> the object returned is not a collection so .count or .item does not work on
> it. I did not look how to use the Iwbemobject type of object that it
> returns.
>
> As a final word of advice, you will need to constantly be thinking about
> each object you acquire and remember for call release to avoid memory leaks.
>
> Jim Kane
>
Printed May 3, 2024, 8:58 am
This article has been viewed/printed 35118 times.
Google search
has resulted in 218 hits on this article since January 25, 2004.