PRB: Marshaling Support for VT_DISPATCH Not Compatible (326202)

MORE INFORMATION

On the common language runtime, the following COM types are all marshaled to managed code as System.Object:

• IUnknown
• IDispatch
• Variant

Because of this limitation, the following behavior might occur if you use a COM object of type IATLSimpleServer:

import atltestsever.*;
import com.ms.com.*;

public class Class1
{
	public static void main (String[] args)
	{
		IATLSimpleServer s = new ATLSimpleServer();
		Variant v = s.getVariant();
		// VARIANT of type VT_DISPATCH returned from COM
		System.out.println(v.getvt() == Variant.VariantDispatch);
		// true in Visual J++, false on the common language runtime
		System.out.println(v.getvt() == Variant.VariantObject);
		// false in Visual J++, true on the common language runtime
		
		Object obj = v.getObject();
		if (ComLib.supportsInterface(obj, ComLib.IID_IDispatch))
		{
			Dispatch.call(obj, "showMe");
			// late-bound call on dispatch interface
		}
	}
}
				

For more information about COM interop marshaling, visit the following Microsoft Web site: