ExcelDna.ComInterop.ComRegistration.ClassFactory.CreateInstance C# (CSharp) Method

        public HRESULT CreateInstance([In] IntPtr pUnkOuter, [In] ref IID riid, [Out] out IntPtr ppvObject)
        {
            // Suspend the C API (helps to prevent some Excel-crashing scenarios)
            using (XlCall.Suspend())
            {
                ppvObject = IntPtr.Zero;
                object instance = Activator.CreateInstance(_comClass.Type);

                // If not an ExcelRtdServer, create safe wrapper that also maps types.
                if (_comClass.IsRtdServer && !instance.GetType().IsSubclassOf(typeof(ExcelRtdServer)))
                {
                    // wrap instance in RtdWrapper
                    RtdServerWrapper rtdServerWrapper = new RtdServerWrapper(instance, _comClass.ProgId);
                    instance = rtdServerWrapper;
                }

                if (pUnkOuter != IntPtr.Zero)
                {
                    // For now no aggregation support - could do Marshal.CreateAggregatedObject?
                    return ComAPI.CLASS_E_NOAGGREGATION;
                }
                if (riid == ComAPI.guidIUnknown)
                {
                    ppvObject = Marshal.GetIUnknownForObject(instance);
                }
                else
                {
                    ppvObject = Marshal.GetIUnknownForObject(instance);
                    HRESULT hrQI = Marshal.QueryInterface(ppvObject, ref riid, out ppvObject);
                    Marshal.Release(ppvObject);
                    if (hrQI != ComAPI.S_OK)
                    {
                        return ComAPI.E_NOINTERFACE;
                    }
                }
                return ComAPI.S_OK;
            }
        }