Direct3D中COM对象的创建方法及接口查看方式问询

Great question about COM object creation in Direct3D 11! Let's break down your concerns clearly:

Can you use CoCreateInstance() to create Direct3D 11 objects? #

Short answer: No, you can't use CoCreateInstance() directly to create core Direct3D 11 objects like ID3D11Device or ID3D11DeviceContext. Here's why:

• Direct3D 11's core objects don't have registered CLSIDs. Microsoft designed dedicated creation functions like D3D11CreateDevice() and D3D11CreateDeviceAndSwapChain() because initializing these objects requires complex parameters (like adapter selection, feature level support, driver type, and swap chain configuration) that CoCreateInstance()'s generic interface can't accommodate.
• There is no such thing as CLSID_D3D11CreateDevice — that's a function, not a COM class identifier. You don't need to link any special libraries beyond the standard Direct3D 11 libs (d3d11.lib, dxgi.lib) to use the dedicated creation functions.
• That said, some auxiliary Direct3D-related COM objects do support CoCreateInstance(), like IDXGIFactory (with CLSID_DXGIFactory or CLSID_DXGIFactory1), though most developers prefer using CreateDXGIFactory() for simplicity.

How to inspect COM objects and their implemented interfaces? #

There are several practical ways to look up COM objects and their interfaces:

• Use OleView.exe (Windows Object Viewer): This is a built-in Windows tool (part of the Windows SDK) that lets you browse all registered COM classes on your system. You can view their CLSIDs, implemented interfaces, type libraries, and even instantiate objects to test them.
• Parse type libraries: For COM components that provide a type library (.tlb file), you can use tools like tlbimp.exe (a .NET Framework tool) to generate interop assemblies and inspect interface definitions, or dumpbin.exe /exports to examine the component's exported functions and type library references.
• Code-level inspection: In your C/C++ code, you can use QueryInterface() to dynamically check if a COM object supports a specific interface. For more advanced enumeration, you can use COM's IEnumMoniker interface or leverage debug tools to inspect the object's vtable (which lists all implemented interface methods).
• Debugger inspection: In Visual Studio, when debugging, you can inspect a COM object's vtable in the watch window to see the methods of the interfaces it implements. This is more low-level but useful for troubleshooting.

内容的提问来源于stack exchange，提问作者Arshia Tahayori