Re: Advantage of COM - COM Discussion Boards

Rakesh__Patil12-Aug-07 19:03

12-Aug-07 19:03

Can anybody help in how to implement print preview in XOffice source code. Interface is 'IInplacePrintPreview' and method is 'StartPrintPreview'.

problem About DCOM on Windows 2003 Server

kcynic11-Aug-07 16:47

kcynic

11-Aug-07 16:47

I have a DCOM based project.
I use RPC to query database(using SQL Server 2000).
But when the Server program run on Windows 2000 server,the client using the data querying well,that I mean query speed is not slow.
But when I run the service on Windows 2003 Server,the client's query speed is almost as slow as 1 of 8 of running in Windows 2000 Server.

Someone would tell me Why?
Thanks.

GOOD LUCK

Show/hide deskband ?

vilius_m11-Aug-07 10:44

vilius_m

11-Aug-07 10:44

Hi,
I guess that I should use IDockingWindow::ShowDW method, but how do I get
pointer to IDockingWindow ? I want to show/hide Quick Launch deskband.

thanks
Vilius

Com Interop Error ?WMI query language not supported?

Blizzardice10-Aug-07 12:23

Blizzardice

10-Aug-07 12:23

I am working on a tool the uses .net to automate a com program. ESRI ArcDesktop to be exact. My production box started failing on my nightly runs. I get an Exception from HRESULT: 0x80041018 which all I can find is this: http://msdn2.microsoft.com/en-US/library/aa383513.aspx
Which states that :
WBEM_E_INVALID_QUERY_TYPE The requested query language is not supported

2147749912
0x80041018

Does anybody have any ideas?

.net code below

<br />
Private Function PackagePMF(ByVal strPMFFile As String, ByVal strPackageDIR As String) As Boolean<br />
        Dim pPE As IPMFPackage<br />
        Dim pSettings As IPropertySet<br />
        Dim pCancel As ITrackCancel<br />
        Dim pArray As IStringArray<br />
        Dim strFullPMF As String<br />
<br />
        Try<br />
            ts.TraceEvent(TraceEventType.Verbose, 0, "StartPackage Function " & Now)<br />
            pPE = New PackagerEngineClass()<br />
            pSettings = pPE.GetDefaultPackagerSettings()<br />
            pCancel = New CancelTracker<br />
            pArray = New StrArray<br />
<br />
            'All Vector data will be converted to Shapefile.<br />
            'All Raster data will be converted to ERDAS Imagine.<br />
            pSettings.SetProperty("Vector Clip Type", esriAPEVectorClipType.esriAPEVectorClipTypeCopyDataset)<br />
            pSettings.SetProperty("Raster Clip Type", esriAPERasterClipType.esriAPERasterClipTypeCopyRaster)<br />
            pSettings.SetProperty("Package Directory", strPackageDIR)<br />
            Debug.WriteLine("Package Setting Set: " & Now)<br />
<br />
            'Specify the name of the pmf to be packaged<br />
            ts.TraceEvent(TraceEventType.Verbose, 0, "Pmf to be Packages... " & strPMFFile)<br />
            strFullPMF = strPMFFile<br />
            pArray.Add(strFullPMF)<br />
<br />
            'Package the pmf with the specified settings     <br />
            pPE.Package(pSettings, pCancel, pArray) X| Line the code fails on.  X| <br />
            ts.TraceEvent(TraceEventType.Information, 1, "Packaging is complete for : " & strPMFFile)<br />
            Return True<br />
<br />
        Catch ex As Exception<br />
            ts.TraceEvent(TraceEventType.Error, 1, "PackagePMF: " & ex.Message & ex.StackTrace)<br />
            Return False<br />
        Finally<br />
            strPMFFile = Nothing<br />
            strPackageDIR = Nothing<br />
            pPE = Nothing<br />
            pSettings = Nothing<br />
            pCancel = Nothing<br />
            pArray = Nothing<br />
<br />
        End Try<br />
    End Function<br />
<br />

What is difference between BSTR, CComBSTR, _bstr_t

Nandu_77b10-Aug-07 5:00

Nandu_77b

10-Aug-07 5:00

Hi,

Can any tell me what is the difference between BSTR, CComBSTR, _bstr_t? and which one to use when?

and also What is difference between VARIANT, CComVariant, _variant_t? and which one to use when?

Thanks
Nandu.

Re: What is difference between BSTR, CComBSTR, _bstr_t

Michael Dunn10-Aug-07 14:58

Michael Dunn

10-Aug-07 14:58

The Complete Guide to C++ Strings, Part II - String Wrapper Classes[^]

--Mike--
Visual C++ MVP Cool | :cool:

LINKS~! Ericahist | PimpFish | CP SearchBar v3.0 | C++ Forum FAQ

Hungarian notation FTW

Advantage of COM

Nandu_77b10-Aug-07 2:40

Nandu_77b

10-Aug-07 2:40

Hi,

Below is the list of advantages of COM. Please correct me if I am wrong and also let me now whether I covered all the advantages of COM (whether I have missed any of the major advantage of COM )

1) Ease of Application customization
2) Language independent
3) Reuse of application architecture
4) Secure access of object since it is binary format

Let me know if there is a better way to put the above advantages.

Nandu

Re: Advantage of COM

Nandu_77b21-Aug-07 5:22

Nandu_77b

21-Aug-07 5:22

Can any one reply to the above questions.

Thanks in advance,
Nandu

COM excpetions

Nandu_77b10-Aug-07 0:10

Nandu_77b

10-Aug-07 0:10

Hi,

Can any one tell me how to handle exception in COM or provide me the link where I find the relevent information.

Thanks in advance
Nandu

Re: COM excpetions

Jonathan [Darka]10-Aug-07 4:54

Jonathan [Darka]

10-Aug-07 4:54

Hi Nandu,

COM does not throw exceptions as they are language specific and cannot cross the COM boundary.

What usually happens, especially if using #import (visual C++) is that a thin wraper is made around the COM function call, this detects the HRESULT failure of the COM call and throws an exception itself back to your C++ code.

Other languages may do the same, but non of them throw exceptions accross the COM boundary.

regards,

Jonathan Wilkes
Darka[Xanya.net]

Re: COM excpetions

Nandu_77b13-Aug-07 0:25

Nandu_77b

13-Aug-07 0:25

Hi Jonathan Wilkes,

So based on HRESULT we have to handle the sutivation.
ok..Thankyou very much.

regards,
Nandu

Re: COM excpetions

Jonathan [Darka]15-Aug-07 7:26

Jonathan [Darka]

15-Aug-07 7:26

Hi Nandu,

Yes, either process the HRESULTS if using straight COM, but if using the Microsoft #import statement then use exception handling as the wrapper created by the #import call will throw exceptions if the HRESULT is not S_OK.

regards,
Jonathan

Jonathan Wilkes
Darka[Xanya.net]

LockServer function

Nageswara Yao9-Aug-07 0:23

Nageswara Yao

9-Aug-07 0:23

what is the perpose of LockServer() in IClassFactiory

Re: LockServer function

CPallini9-Aug-07 4:55

CPallini

9-Aug-07 4:55

To avoid the COM server deletion whenever the reference count goes to zero. See the MSDN documentation about http://msdn2.microsoft.com/en-us/library/ms682332.aspx[^].
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

COM Runtime Error !!!

GauranG Shah8-Aug-07 20:47

GauranG Shah

8-Aug-07 20:47

Hello

I have Created the Simple ATL COM Server (.dll). and put one interface in it(called MyMath) and Add one function called Addition. I also made a simple MFC application to use the function and import the library using import "..\path\_name.lib"> and then initialize the Interface. So It gives the Compile Time Error Confused | :confused:

. So I include two more files. _server.h and _server_i.c and Bam!!! Smile | :)

Compile Time Error Gone!!.(server is the name of my ATL SERVER Project )But when I run the Programme it gives me the Run time Error as Below.
the instruction at "0X004139d8"referenced memory at "0z00000000". The memory coult not be "read" Cry | :((

I am Using Visual Studio .Net 2003 for making Application

So Please Help Me.

Re: COM Runtime Error !!!

«_Superman_»9-Aug-07 23:32

«_Superman_»

9-Aug-07 23:32

For the compile error try this
#import "..\path\_name.lib" no_namespace

« Superman »

Re: COM Runtime Error !!!

prasad_som9-Aug-07 23:51

prasad_som

9-Aug-07 23:51

Would you provide some relevant code ?

Prasad
MS MVP - VC++

Re: COM Runtime Error !!!

jonnynolimits10-Aug-07 1:56

jonnynolimits

10-Aug-07 1:56

Hello,
One thing that you can do is to generate the map file during the compilation and then, reading that, find the line of code that generates the crash.

An excellent article is at url:
www.codeproject.com/debug/mapfile.asp

I don't know if, in your case, my idea can be usefull, but...

Word COM

Spaz808-Aug-07 5:31

Spaz80

8-Aug-07 5:31

Hello

Im trying to deploy a application created on a machine with Office2007 on a new machine witch is using Office 2003. Im not getting it... I continue getting this error...

Unable to cast COM object of type 'Microsoft.Office.Interop.Word.ApplicationClass' to interface type 'Microsoft.Office.Interop.Word._Application'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{00020970-0000-0000-C000-000000000046}' failed due to the following error: Library not registered. (Exception from HRESULT: 0x8002801D (TYPE_E_LIBNOTREGISTERED)).

Just wondering if any of you guys know what could be wrong

Cheers

Spaz

creating/exposing global members in an ATL COM DLL

zgilboa7-Aug-07 17:41

zgilboa

7-Aug-07 17:41

Greetings.

I have created a DLL using the ATL COM AppWizard, and have successfully added a class and functions. I was also successful in create and an expose an enum by including

typedef enum {aa,bb,cc} testEnum;

in the .idl file.

PROBLEM: how do I add definitions of global members? In other words, I would like some constants, variables and functions to be immediately available to VB applications that use my dll, in the same way that the "Load" method or the "App" property become available once the a reference to VB6.olb is created.

Thanks,

zgilboa

Re: creating/exposing global members in an ATL COM DLL

prasad_som7-Aug-07 20:29

prasad_som

7-Aug-07 20:29

Probaly, this[^] article helps you.

Prasad
MS MVP - VC++

Re: creating/exposing global members in an ATL COM DLL

zgilboa8-Aug-07 6:17

zgilboa

8-Aug-07 6:17

Thanks. Another thing which I've found out and which solves it is the use of the IDL appobject attribute. Each coclass that has this attribute included in its IDL definition will expose all of its members as global members. Additionally, you could use this attribute with more than one coclass.

[
uuid(483771F3-DD5D-4168-8DC6-CE090E2733F8),
appobject,
helpstring("RefRate Class")
]
coclass RefRate
{
[default] interface IRefRate;
};

zgilboa

How to derive from a existing Interface?

donguy767-Aug-07 16:34

donguy76

7-Aug-07 16:34

I have a COM dll written using ATL. There is a interface named
"IVehicle". I want to derive 2 new interfaces from this, named
"IToyota" and "IHonda". How can i do that?

The purpose of doing this is that i should be able to use functions
inside both Base interface(IVehicle) from the drived new interfaces.

Thanks in advance.

Re: How to derive from a existing Interface?

prasad_som7-Aug-07 20:27

prasad_som

7-Aug-07 20:27

donguy76 wrote:
How can i do that?

You can do this, same way as simple class,

//idl code
interface IToyoto  : Vehicle
{...

donguy76 wrote:
The purpose of doing this is that i should be able to use functions
inside both Base interface(IVehicle) from the drived new interfaces.

You should remember, COM support interface inheritance, not implementation inheritance.

In other words, you need to implement all function inherited by new interface.

Prasad
MS MVP - VC++

Difference between win32 dll and com dll

Nandu_77b7-Aug-07 2:47

Nandu_77b

7-Aug-07 2:47

There is question Difference between win32 dll and com dll?

DLL is a comman one there is nothing like win32 dll and COM dll. COM makes use of dll for dynamic linking.

Can you please provide me more information about the same and also Please correct me if I am wrong.

Thanks in advance,

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