DynamicHostObject in V8: function is invoked as property

[DavidBal]

Hi ClearScript-Team,

i have a problem when using the DynamicHostObject with ClearScript.V8:

const comobject = COMObjectProvider.createCOMObject("Excel.Sheet");

comobject.Application.Workbooks.Open("C:\\temp\\Sample.xlsx");

The Open function call, invokes the TryGetMember function on the DynamicHostObject.

Is there any way that function calls invokes TryInvokeMember function on the DynamicHostObject directly?

(I think the problem is that every function on a object in js is a property which returns a delegate/function "object".)

Kind regards,
David

[ClearScriptLib]

Hi David,

I think the problem is that every function on a object in js is a property which returns a delegate/function "object".

That's correct. V8’s embedding API mirrors JavaScript semantics, in which there's no primitive method call operation. Instead, method call syntax is desugared into property access followed by a function call. Embedders like ClearScript can intercept those individual steps, but V8 provides no hook for intercepting the combined operation.

When asked to retrieve a property that's actually a method, ClearScript returns an invocable object – a host method. V8 recognizes that as a function and calls it. That's how all .NET and COM method invocation works in ClearScript with V8.

Thanks!