Any code to replace document.AcadDocument (object)

#1
The following code is a part of code to display preview image of blocks.
but the intellicad c# api do not have doc.AcadDocument.
Have any suggest code to use instead of "doc.AcadDocument" ?
Thanks

object ActiveDocument = doc.AcadDocument;
object[] data = { "_.BLOCKICON " + blk.Name + "\n" };
ActiveDocument.GetType().InvokeMember("SendCommand", System.Reflection.BindingFlags.InvokeMethod, null, ActiveDocument, data);