Getting object AcadSelectionSet to select entire drawing

I'm trying to get AcadSelectionSet to select an entire drawing pulled up as an AcadDocument! The following is what I have:

Dim acadApp As AutoCAD.AcadApplication
Dim acadDoc As AutoCAD.AcadDocument
Dim objSelection As AutoCAD.AcadSelectionSet

Set acadDoc = GetObject(strPath)
'strPath is a text box with the entire filename path of a .dwg file
Set acadApp = acadDoc.Application
Set objSelection = ????

Not sure how to properly show Set objSelection without putting add in there to do so? I know eventually I will have to do a acSelectionSetAll to pull up everything in a window but not sure on the correct format?

Is there also a way to define objSelection even more with just selecting all blocks that happen to be labeled as door_TAG?

 

as an AcadDocument! The following is what I have:

Set objSelection=acadDoc.SelectionSets.Add("MySet")
objSelection.Select acSelectionSetAll

In above code, if the current opened drawing has already had a SelectionSet
called "MySet" in it, you will got runtime error. When programmatically
adding a SelectionSet, I always loop through the Document.SelectionSets
collection to make sure there is no SelectionSet with the same name.

there to do so? I know eventually I will have to do a acSelectionSetAll to
pull up everything in a window but not sure on the correct format?

all blocks that happen to be labeled as door_TAG?

 

An alternative method is to use error trapping and unconditionally add
the set followed by clearing it.