How to change the ComHost Server registry name?

[forderud]

I'm working on a plugin-based application architecture that relies on custom naming of the COM server classes in the registry. The <project>.comhost.dll COM server generated for projects relying on <EnableComHosting> today always seem to be named CoreCLR COMHost Server which says nothing about the COM server. I am therefore seeking a mechanism for either more informative default naming or an ability to override the name.

Is there a mechanism for customizing the COMHost server name to something else than "CoreCLR COMHost Server"?

Steps to reproduce

1. Build the https://github.com/dotnet/samples/tree/main/core/extensions/COMServerDemo/COMServer
2. Register COMServer.comhost.dll with regsvr32.exe
3. Open RegEdit.exe and observe that the server name is "CoreCLR COMHost Server" in the Computer\HKEY_CLASSES_ROOT\CLSID{DB1797F5-7198-4411-8563-D05F4E904956} registry folder:
   

.Net framework behavior

The .Net framework 4.x solved this problem for projects enabling "Register for COM interop" by using the same ProgId string also for the COM server name. Using the same naming scheme also in .Net core would be an acceptable outcome for me.

I couldn't figure out the best area label to add to this issue. If you have write-permissions please help me learn by adding exactly one area label.

[jkoritzinsky]

We currently don't support customizing this name, but this is something that we can consider for the future.

Tagging subscribers to this area: @vitek-karas, @agocke, @VSadov
See info in area-owners.md if you want to be subscribed.

Issue Details

---

I'm working on a plugin-based application architecture that relies on custom naming of the COM server classes in the registry. The <project>.comhost.dll COM server generated for projects relying on <EnableComHosting> today always seem to be named CoreCLR COMHost Server which says nothing about the COM server. I am therefore seeking a mechanism for either more informative default naming or an ability to override the name.

Is there a mechanism for customizing the COMHost server name to something else than "CoreCLR COMHost Server"?

Steps to reproduce

1. Build the https://github.com/dotnet/samples/tree/main/core/extensions/COMServerDemo/COMServer
2. Register COMServer.comhost.dll with regsvr32.exe
3. Open RegEdit.exe and observe that the server name is "CoreCLR COMHost Server" in the Computer\HKEY_CLASSES_ROOT\CLSID{DB1797F5-7198-4411-8563-D05F4E904956} registry folder:
   

.Net framework behavior

The .Net framework 4.x solved this problem for projects enabling "Register for COM interop" by using the same ProgId string also for the COM server name. Using the same naming scheme also in .Net core would be an acceptable outcome for me.

Author:	forderud
Assignees:	-
Labels:	area-Host, untriaged
Milestone:	-

[jkoritzinsky]

cc: @AaronRobinsonMSFT @elinor-fung

[AaronRobinsonMSFT]

Hi @forderud. This is a reasonable request. When the feature was first ported, we didn't support ProgIDs so missed that compat point. Something to consider here though, which ProgID? Server assemblies can contain multiple servers which can make this hard. I suppose we could just select the first one we find. Perhaps we could also put in the assembly name? For example, Foo.dll could become Foo.

We are also open to other suggestions.

[AaronRobinsonMSFT]

Instead of using the constant, use something from the supplied const comhost::clsid_map_entry.

runtime/src/native/corehost/comhost/comhost.cpp

Lines 342 to 352 in b2dc37b

	// Set the default value for all COM host servers
	const WCHAR defServerName[] = _X("CoreCLR COMHost Server");
	res = ::RegSetValueExW(
	regKey.get(),
	nullptr,
	0,
	REG_SZ,
	reinterpret_cast<const BYTE*>(defServerName),
	static_cast<DWORD>(sizeof(defServerName)));
	if (res != ERROR_SUCCESS)
	return __HRESULT_FROM_WIN32(res);

[forderud]

... Something to consider here though, which ProgID? Server assemblies can contain multiple servers which can make this hard. I suppose we could just select the first one we find. Perhaps we could also put in the assembly name? For example, Foo.dll could become Foo.

There's is usually a 1-to-1 relationship between ProgID and COM classes, so that shouldn't be an issue. Servers containing multiple
COM classes will also expose multiple ProgIDs.

We are also open to other suggestions.

Concrete suggestion for a "MyComServer" project containing two COM classes (FirstClass and SecondClass):

• File naming: MyComServer.dll and MyComServer.comhost.dll (as before)
• 1st COM class: ProgID "MyComServer.FirstClass" (as before), name "MyComServer.FirstClass" (instead of "CoreCLR COMHost Server"
• 2nd COM class: ProgID "MyComServer.SecondClass" (as before), name "MyComServer.SecondClass" (instead of "CoreCLR COMHost Server")

This will both yield more descriptive names and make the implementation consistent with .Net framework 4.x.

It would also be nice to also be able to override the default name with e.g. the [Description("..")] attribute for the class if available, or something similar.