/// <summary>
/// A basic helper for IDispatch::Invoke
/// </summary>
/// <param name="obj">The IDispatch object of which you want to invoke a member on</param>
/// <param name="memberId">The dispatch ID of the member to invoke</param>
/// <param name="invokeKind">See InvokeKind enumeration</param>
/// <param name="args">Array of arguments to pass to the call, or null for no args</param>
/// <remarks>TODO support DISPATCH_PROPERTYPUTREF (property-set) which requires special handling</remarks>
/// <returns>An object representing the return value from the called routine</returns>
public static object Invoke(IDispatch obj, int memberId, InvokeKind invokeKind, object[] args = null)
{
var pDispParams = PrepareDispatchArgs(args);
var pExcepInfo = new ComTypes.EXCEPINFO();
int hr = obj.Invoke(memberId, ref GUID_NULL, 0, (uint)invokeKind,
ref pDispParams, out object pVarResult, ref pExcepInfo, out uint pErrArg);
UnprepareDispatchArgs(pDispParams);
if (ComHelper.HRESULT_FAILED(hr))
{
if ((hr == (int)KnownComHResults.DISP_E_EXCEPTION) && (ComHelper.HRESULT_FAILED(pExcepInfo.scode)))
{
throw Marshal.GetExceptionForHR(pExcepInfo.scode);
}
throw Marshal.GetExceptionForHR(hr);
}
return(pVarResult);
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="outerObject">The object that needs interface requests filtered</param>
/// <param name="queryForType">determines whether we call QueryInterface for the interface or not</param>
/// <remarks>if the passed in outerObject is known to point to the correct vtable for the interface, then queryForType can be false</remarks>
/// <returns>if outerObject is IntPtr.Zero, then a null wrapper, else an aggregated wrapper</returns>
public RestrictComInterfaceByAggregation(IntPtr outerObject, bool queryForType = true)
{
if (queryForType)
{
var IID = typeof(T).GUID;
if (ComHelper.HRESULT_FAILED(Marshal.QueryInterface(outerObject, ref IID, out _outerObject)))
{
// allow null wrapping here
return;
}
}
else
{
_outerObject = outerObject;
Marshal.AddRef(_outerObject);
}
var aggObjPtr = Marshal.CreateAggregatedObject(_outerObject, this);
WrappedObject = (T)Marshal.GetObjectForIUnknown(aggObjPtr); // when this CCW object gets released, it will free the aggObjInner (well, after GC)
Marshal.Release(aggObjPtr); // _wrappedObject holds a reference to this now
}