Loading .NET UserControls in IE with .NET 4.0

Question

I\'ve got a legacy app where there\'s a UserControl which is used as an activex in a web page loaded in IE. Before .NET 4.0, there were security policies and a MMC console

Answer 1

Hosting controls in IE is now blocked by default (as of v4 or v4.5). See MSDN article under 'Web Applications'.

Fortunately it is super-easy to re-enable the functionality with these reg keys:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\.NETFramework]
"EnableIEHosting"=dword:00000001

[HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\.NETFramework]
"EnableIEHosting"=dword:00000001

The x64 key was the one that fixed it for me, running IE8 (x32) on Win7 (x64) using a .Net v3.5 SP1 control compiled for x32.