Re: COM Expertise needed: COM Callbacks

[John Chapman via Digitalmars-d-learn]

On Tuesday, 25 April 2017 at 18:39:56 UTC, Nierjerson wrote:
void RGB(icRGBColor ic, cSolidColor s)
{
        import main;
        EXCEPINFO exception;
        uint argErr = 0;
        auto iidNULL = IID_NULL;
        auto RT = new SafeVariantPtr();
        VARIANT[1] paramVars;
	DISPPARAMS params = {rgvarg: paramVars.ptr, cArgs: 1, 
cNamedArgs: 0};
        auto ID = s.COMMethodIDs[`RGB`];
	paramVars[0].punkVal = ic; paramVars[0].vt = 
VARENUM.VT_DISPATCH; scope(exit) VariantClear(&paramVars[0]);
	auto res = s.iDispatch.Invoke(cast(int)ID, &iidNULL, 0, 
DISPATCH_PROPERTYPUT, &params, cast(VARIANT*)RT, &exception, 
&argErr);
	assert(res == S_OK, `Could not invoke COM Function 
cSolidColor.RGB. Error `~to!string(res, 16));

}

When you use DISPATCH_PROPERTYPUT you need to set cNamedArgs and 
rgdispidNamedArgs like so:

  int dispidNamed = DISPID_PROPERTYPUT;
  params.cNamedArgs = 1;
  params.rgdispidNamedArgs = &dispidNamed;

You should also call AddRef on any COM objects you add to your 
paramVars array.