Why AutoCAD2008. NET extensions can be based on. NET 3.5

We know that the. NET version of AutoCAD2008 (which also includes 2007 and 2009) is 2.0, but its. net extension's "Target framework" can choose the. NET Framework 3.5, which is why?

Found the answer in this blog post.

Using the. NET Framework 4.0 in various AutoCAD versions

We is currently compiling our extensions with. NET 3.5 (which uses CLR 2.0), and they work fine for AutoCAD 2008-2011.

Please look at this chart

Visual Studio CLR. NET Framework------------------------------------------------ ----------------------------------------Visual Studio. NET (Ranier) 1.0.3705 1.0Visual Studio 2003 (Everett) 1.1.4322 1.1Visual Studio 2005 (Whidbey) 2.0.50727 2.0Visual Studio 2 005 with. NET 3.0 Extensions 2.0.50727 2.0, 3.0Visual Studio (Orcas) 2.0.50727 2.0 SP1, 3.0 SP1, 3.5Visual Studio SP1 2.0.50727 2.0 SP2, 3.0 SP2, 3.5 sp1visual Studio (Hawai i) 4.0.30319 4.0

Even though the. NET Framework version is inconsistent,programs are compatible as long as the CLR version is consistent.

The following is a list of the history of some versions of AutoCAD, and the corresponding relationship with VS versions

ACAD Version History
Version Internal version AutoCAD versions VS/VC versions
DWG 2000 AC1015AutoCAD 2000i, AutoCAD 2002 (VC6.0) R15
DWG 2004 AC1018AutoCAD 2004, AutoCAD 2005, AutoCAD 2006 (VS2002 VC7.0) R16
DWG 2007 AC1021AutoCAD, AutoCAD, AutoCAD (VS2005 VC8.0) R17
DWG 2010 AC1024AutoCAD, AutoCAD, AutoCAD (VS2008 VC9.0) R18
DWG 2013 AC1027AutoCAD, AutoCAD, AutoCAD 2015? (VS2010 VC10) R19

So it's easy to see autocad2007-2012, extensions can be developed based on. NET framework 3.5.