IContextCallback.cs

using System;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Text;
using WinRT;
using WinRT.Interop;

#pragma warning disable 0169 // warning CS0169: The field '...' is never used
#pragma warning disable 0649 // warning CS0169: Field '...' is never assigned to

namespace WinRT.Interop
{
    struct ComCallData
    {
        public int dwDispid;
        public int dwReserved;
        public IntPtr pUserDefined;
    }

    unsafe delegate int PFNCONTEXTCALL(ComCallData* data);

    [Guid("000001da-0000-0000-C000-000000000046")]
    unsafe interface IContextCallback
    {
        // The pUnk parameter is intentionally excluded here
        // since it is required to always be null.
        void ContextCallback(
            PFNCONTEXTCALL pfnCallback,
            ComCallData* pParam,
            Guid riid,
            int iMethod);
    }
}


namespace ABI.WinRT.Interop
{
    [Guid("000001da-0000-0000-C000-000000000046")]
    unsafe class IContextCallback : global::WinRT.Interop.IContextCallback
    {
        [Guid("000001da-0000-0000-C000-000000000046")]
        public struct Vftbl
        {
            global::WinRT.Interop.IUnknownVftbl IUnknownVftbl;
            private void* _ContextCallback;
            public delegate* unmanaged[Stdcall]<IntPtr, IntPtr, ComCallData*, Guid*, int, IntPtr, int> ContextCallback_4
            {
                get => (delegate* unmanaged[Stdcall]<IntPtr, IntPtr, ComCallData*, Guid*, int, IntPtr, int>)_ContextCallback;
                set => _ContextCallback = (void*)value;
            }
        }
        public static ObjectReference<Vftbl> FromAbi(IntPtr thisPtr) => ObjectReference<Vftbl>.FromAbi(thisPtr);

        public static implicit operator IContextCallback(IObjectReference obj) => (obj != null) ? new IContextCallback(obj) : null;
        public static implicit operator IContextCallback(ObjectReference<Vftbl> obj) => (obj != null) ? new IContextCallback(obj) : null;
        protected readonly ObjectReference<Vftbl> _obj;
        public IntPtr ThisPtr => _obj.ThisPtr;
        public ObjectReference<I> AsInterface<I>() => _obj.As<I>();
        public A As<A>() => _obj.AsType<A>();
        public IContextCallback(IObjectReference obj) : this(obj.As<Vftbl>()) { }
        public IContextCallback(ObjectReference<Vftbl> obj)
        {
            _obj = obj;
        }

        private unsafe struct ContextCallData
        {
            public IntPtr delegateHandle;
            public ComCallData* userData;
        }

        private const int RPC_E_DISCONNECTED = unchecked((int)0x80010108);

        public unsafe void ContextCallback(global::WinRT.Interop.PFNCONTEXTCALL pfnCallback, ComCallData* pParam, Guid riid, int iMethod)
        {
            var callback = Marshal.GetFunctionPointerForDelegate(pfnCallback);
            var result = _obj.Vftbl.ContextCallback_4(ThisPtr, callback, pParam, &riid, iMethod, IntPtr.Zero);
            GC.KeepAlive(pfnCallback);
            if (result != RPC_E_DISCONNECTED)
            {
                Marshal.ThrowExceptionForHR(result);
            }
        }
    }
}