Open drawing in SDI mode

this is another question about VB.NET

Our drawing files are numbered in such a way that you can get to the next sheet by adding 1 to the current drawing. After a while you have to reset the sheet number back to 1 and increment another part of the file. This is all quite simple.

I used to have a LIPS routine that opened the next or previous drawing. I have re-written this with success in VBA so thought it would be a good start for my adventures into VB.NET

I have got the tricky part of the routine (determining the next file name) working but cannot find how to open that in SDI mode. There are several reasons for wanting to utilise SDI mode, the biggest of which is that I want to.

Does anybody know if it is possible?

Maybe the system variable SDI would help. The following was copied from the express tools System Variable Editor:

Controls whether AutoCAD runs in single- or multiple-document interface. Helps third-party developers update applications to work smoothly with the AutoCAD multiple-drawing mode.

0 Turns on multiple-drawing interface.

1 Turns off multiple-drawing interface.

2 (Read-only) Multiple-drawing interface is disabled because AutoCAD has loaded an application that does not support multiple drawings. SDI

I had forgotten the third variation, I will give that a try tomorrow.

The problem I have is that if I try a

Application.DocumentManager.Open(ThisDrawingPath & myDWGName & ".dwg", False)

I just get an error message saying "Method not available in SDI mode"

(sorry, should have said that earlier)