BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Access Active Desktop items          BorlandTalk.com Forum Index -> comp.lang.pascal.delphi.misc View previous topic :: View next topic   Author Message Michael Evans Guest Posted: Thu Jan 12, 2006 8:06 pm    Post subject: Access Active Desktop items Hi, I'm trying to access desktop items on the Windows Active Desktop. Active Desktop is enabled and there are two desktop items. I can get the correct count of items, but using GetDesktopItem to access an item always fails. I'm using Delphi 7, running on Windows XP. Does anyone know what the problem is? procedure TForm1.Button4Click(Sender: TObject); const CLSID_ActiveDesktop: TGUID = '{75048700-EF1F-11D0-9888-006097DEACF9}'; var ActiveDesktop: IActiveDesktop; Count : Integer; Result : Integer; ItemProperties: TShComponent; begin ActiveDesktop := CreateComObject(CLSID_ActiveDesktop) as IActiveDesktop; ActiveDesktop.GetDesktopItemCount(Count, 0); //gets correct count Result := ActiveDesktop.GetDesktopItem(0, ItemProperties, 0); //returns -2147024809 end; Regards Michael Evans Back to top Maarten Wiltink Guest Posted: Thu Jan 12, 2006 10:03 pm    Post subject: Re: Access Active Desktop items "Michael Evans" <michael (AT) otherNOSPAMsoft (DOT) com> wrote Quote: I'm trying to access desktop items on the Windows Active Desktop. Active Desktop is enabled and there are two desktop items. I can get the correct count of items, but using GetDesktopItem to access an item always fails. I'm using Delphi 7, running on Windows XP. [...] ActiveDesktop.GetDesktopItemCount(Count, 0); //gets correct count Result := ActiveDesktop.GetDesktopItem(0, ItemProperties, 0); //returns -2147024809 Googling for the hexadecimal representation of that number seems to indicate it means "invalid parameter value" and can sometimes be fixed by installing a newer DirectX. Groetjes, Maarten Wiltink Back to top Michael Evans Guest Posted: Fri Jan 13, 2006 6:21 am    Post subject: Re: Access Active Desktop items Quote: Googling for the hexadecimal representation of that number seems to indicate it means "invalid parameter value" and can sometimes be fixed by installing a newer DirectX. Thanks. I don't think that the GetDesktopItem uses DirectX. Searching for that error message I found that it means ""invalid parameter value" but I didn;t see anyhting about DirectX. Looking at the documentation for it, it's expecting an LPCOMPONENT structure as the 2nd argument. In Delphi's ShlObj.pas it's defined in the format of the IE4COMPONENT structure. Also, GetDesktopItem says it's supported on Windows 2000/ME. Does anyone know a way to do this under Windows XP (and Windows 98 if possible). GetDesktopItem Documentation: http://msdn.microsoft.com/library/default.asp?url=/library/en- us/shellcc/platform/shell/reference/ifaces/iactivedesktop/GetDesktopItem ..asp Component Structure Documentation: http://msdn.microsoft.com/library/default.asp?url=/library/en- us/shellcc/platform/shell/reference/structures/component.asp IE4COMPONENT Structure Documentation: http://msdn.microsoft.com/library/default.asp?url=/library/en- us/shellcc/platform/shell/reference/structures/ie4component.asp Regards Michael Back to top Rob Kennedy Guest Posted: Fri Jan 13, 2006 6:54 am    Post subject: Re: Access Active Desktop items Michael Evans wrote: Quote: I'm trying to access desktop items on the Windows Active Desktop. Active Desktop is enabled and there are two desktop items. I can get the correct count of items, but using GetDesktopItem to access an item always fails. I'm using Delphi 7, running on Windows XP. Does anyone know what the problem is? procedure TForm1.Button4Click(Sender: TObject); const CLSID_ActiveDesktop: TGUID = '{75048700-EF1F-11D0-9888-006097DEACF9}'; var ActiveDesktop: IActiveDesktop; Count : Integer; Result : Integer; ItemProperties: TShComponent; begin ActiveDesktop := CreateComObject(CLSID_ActiveDesktop) as IActiveDesktop; ActiveDesktop.GetDesktopItemCount(Count, 0); //gets correct count Result := ActiveDesktop.GetDesktopItem(0, ItemProperties, 0); //returns -2147024809 Note that GetDesktopItem does not return an Integer. It returns an HResult, which is a COM error code. (Change the Result variable's declaration accordingly.) You can use the ComCheck procedure to turn such an error code into an exception with an error message. Also note that GetDesktopItemCount is a not a procedure. It is a function, and it returns an HResult that you should check before proceeding. Just because the Count parameter get filled with the value you expected doesn't necessarily mean the function's result was S_OK. I think the newsgroup archives will show that I'm paranoid about checking return values from API functions. If ItemProperties is indeed declared as the correct type, try setting its dwSize parameter before you call GetDesktopItem. And if that doesn't work, then try calling ZeroMemory on the record before you set the size. Forgetting to set the record size for an API function is consistent with a return value of E_InvalidArg. -- Rob Back to top Michael Evans Guest Posted: Fri Jan 13, 2006 5:13 pm    Post subject: Re: Access Active Desktop items Quote: Note that GetDesktopItem does not return an Integer. It returns an HResult, which is a COM error code. Thanks, I've changed the code to use this. Quote: If ItemProperties is indeed declared as the correct type, try setting its dwSize parameter before you call GetDesktopItem. And if that doesn't work, then try calling ZeroMemory on the record before you set the size. I tried setting dwSize but that didn't help. Not sure if I used ZeroMemory correctly as that didn't work either. procedure TForm1.Button4Click(Sender: TObject); const CLSID_ActiveDesktop: TGUID = '{75048700-EF1F-11D0-9888-006097DEACF9}'; var ActiveDesktop: IActiveDesktop; Count : Integer; Result : HResult; Item : TShComponent; begin ActiveDesktop := CreateComObject(CLSID_ActiveDesktop) as IActiveDesktop; Result := ActiveDesktop.GetDesktopItemCount(Count, 0); OleCheck(Result); //no error Item.dwSize := SizeOf(Item); ZeroMemory(@Item, SizeOf(TShComponent)); Result := ActiveDesktop.GetDesktopItem(0, Item, 0); OleCheck(Result); //Error - The Parameter is incorrect. end; Regards Michael Back to top Hans-Peter Diettrich Guest Posted: Fri Jan 13, 2006 9:26 pm    Post subject: Re: Access Active Desktop items Rob Kennedy schrieb: Quote: Note that GetDesktopItem does not return an Integer. It returns an HResult, which is a COM error code. (Change the Result variable's declaration accordingly.) You can use the ComCheck procedure to turn such an error code into an exception with an error message. The SafeCall calling convention automagically checks the HResult, and returns the result of the function (if it is a function). Without SafeCall, every method is wrapped into a function, which returns an HResult error code. When the wrapped method is a function, the result is returned in a var parameter, added to the parameter list. The declarations should be checked for the calling convention, and the function/procedure calls then can be handled accordingly. In the environment options you can select whether you want safecall (preferred) or stdcall calling convention in the type library editor/importer. DoDi Back to top Rob Kennedy Guest Posted: Sat Jan 14, 2006 7:55 pm    Post subject: Re: Access Active Desktop items Hans-Peter Diettrich wrote: Quote: The SafeCall calling convention automagically checks the HResult, and returns the result of the function (if it is a function). Without SafeCall, every method is wrapped into a function, which returns an HResult error code. When the wrapped method is a function, the result is returned in a var parameter, added to the parameter list. But IActiveDesktop does not use safecall, and it is declared in ShlObj.pas, which was not generated by the type-library importer. -- Rob Back to top alanglloyd@aol.com Guest Posted: Sat Jan 14, 2006 10:40 pm    Post subject: Re: Access Active Desktop items MSDN reference for COMPONENT structure (== Delphi TShComponent I believe) also refers to a COMPPOS and a COMPSTATEINFO structure (csiOriginal & csiRestored) referenced in the COMPONENT structure. I would imagine you would have to supply, zero, and dwSize these other structures before the GetDeskTopItem genie was happy. You might have to troll through ShObj.pas to identify the Delphi name of these two structure types in TShComponent. Alan Lloyd Back to top Michael Evans Guest Posted: Sun Jan 15, 2006 11:57 am    Post subject: Re: Access Active Desktop items In article <1137278402.876014.45640 (AT) f14g2000cwb (DOT) googlegroups.com>, [email]alanglloyd (AT) aol (DOT) com[/email] says... Quote: MSDN reference for COMPONENT structure (== Delphi TShComponent I believe) also refers to a COMPPOS and a COMPSTATEINFO structure (csiOriginal & csiRestored) referenced in the COMPONENT structure. I would imagine you would have to supply, zero, and dwSize these other structures before the GetDeskTopItem genie was happy. You might have to troll through ShObj.pas to identify the Delphi name of these two structure types in TShComponent. Alan Lloyd I've got it working now. Thanks for everyones help. TShComponent in Delphi's ShlObj.pas is the older IE4COMPONENT component structure. I found an update called ShlObjAdditional by Daniel U. Thibault which contains the correct structure. The following code works: const CLSID_ActiveDesktop: TGUID = '{75048700-EF1F-11D0-9888-006097DEACF9}'; var ActiveDesktop: IActiveDesktop; Count : Integer; Item : TIE5Component; begin ActiveDesktop := CreateComObject(CLSID_ActiveDesktop) as IActiveDesktop; OleCheck(ActiveDesktop.GetDesktopItemCount(Count, 0)); Item.dwSize := SizeOf(Item); OleCheck(ActiveDesktop.GetDesktopItem(1, @Item, 0)); end; regards Michael Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> comp.lang.pascal.delphi.misc All times are GMT Page 1 of 1   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.