how to use windows-rs com function CLSIDFromProgID.

Question

how to use windows-rs com function CLSIDFromProgID.

tab shi 20

Hello, everyone. I am now using windows-rs to migrate previous vb programs. The vb program references a library class. I checked this class through ole/com and found it in Type Libraies, and in HKEY_CLASSES_ROOT in the registry editor, it appears in typeid. I now know that you can use it by letting clsid = CLSIDFromProgID(PCWSTR::from_raw(HSTRING::from("Excel.Aplication").as_ptr(),))?; Gets the clsid of this class. But I don't know how to get classes in typeid?

User's image

Accepted answer

0 additional answers

Your answer

Answer 1

RLWA32 49,551

Your question is not clear to me. COM objects are instantiated based on their CLSID. The GUID of a type library has been used by C# or VB projects to create a project refererence. The creation of a project reference is done through the Visual Studio IDE, not programmatically.

For what purpose do you need to programmatically determine the GUID of a type library?

You can use the oleview.exe utility to inspect the contents of a type library to see which COM classes (coclass) it describes.

For example, examining the type library for Windows Update shows this -

WUtlb

Note the highlighted button in the toolbar. That provides the organized treeview of the type library contents. If you expand the CoClasses tree item you can see all of the COM classes described in the library. If you select any of the items in the expansion of CoClasses the pane on the rights side of the window will display information about the CoClass, including its GUID (uuid in the display).

tab shi 20 Reputation points

2024-08-14T00:56:27.24+00:00

Thanks, I have used oleview. exe to view the library class. But how to connect to this class using windows-rs(windows 'rust library).

This is the source code for Excel.application.Get clsid through Excel.application

So how do other libraries get this name similar to Excel.application.

Then I replaced "Excess.Application" with the following code "WBC_KrcLib.SyncMessage" and an error occurred during the compilation run
RLWA32 49,551 Reputation points

2024-08-14T06:31:03.9066667+00:00

The posted code is assuming that a PROGID of WBC_KRCLIB.SyncMessage exists! That may not be the case. Additionally, look at the right side pane for the MIDL attributes that appear right before the coclass statement. Do you see that it says "noncreatable"? That is an indication that this COM object is not intended to be directly created -- see the documentation of the noncreatable attribute for additional information.

Back to the general case. All that is needed to instantiate a COM object is a valid CLSID. You can see the CLSID of a coclass displayed by the type library viewer. You could use that CLSID directly.

If a PROGID for the COM Object exists you obtain it by calling the ProgIDFromCLSID function.
RLWA32 49,551 Reputation points

2024-08-14T09:46:15.5366667+00:00

By the way, error code 0x800401F3 means "Invalid class string".

Share via

how to use windows-rs com function CLSIDFromProgID.

0 additional answers

Your answer