Sql Server CLR load assembly failed

Acording to the documentation, any .NET assembly can be referenced but each dependant assembly must also be registered in the database (visible in the "Programmability - Assemblies" node in SQL Server Manager).Once the SQL Server Database has the dependant assemblies available they will be present in the Add Reference Dialog window in Visual Studio.

This SQL code below works. I had needed the System.Web.dll assembly(you need the correct version my 2005 SQL is 64 bit)

CREATE ASSEMBLY [System.Web] AUTHORIZATION dbo FROM 'c:\WINDOWS\Microsoft.NET\Framework64\v2.0.50727\System.web.dll'WITH PERMISSION_SET = UNSAFE 

The system will try to automatically register dependent assemblies but can only do it from the same directory as the file you are attempting to register.In my case it also registered the following assemblies in the database for System.Web to operate correctly...

System.Configuration.Install    System.Design   System.DirectoryServices    System.DirectoryServices.Protocols  System.Drawing  System.Drawing.Design   System.EnterpriseServices   System.Runtime.Remoting System.Runtime.Serialization.Formatters.Soap    System.ServiceProcess   System.Web.RegularExpressions   System.Windows.Forms

My system is using 3.5 Framework so I cannot test importing System.Web.Extensions.dll for you but it may require other assemblies from another folder to register, and since it is a 4.0 assembly it may be referencing some 2.0 or 3.5 assemblies that are in a different folder.

I suspect you will end up with a rather large list of assemblies imported to get it to work but it is definitly possible to do.The operation can probably be done more easily by having one folder with all the dependent dlls in it and register from there.

Sadly integration of the .NET Framework CLR with SQL Server 2005 / 2008 is only a limited subset of the framework and the System.Web.Extensions doesn't seem to be a supported assembly / namespace.

For a full list of supported assemblies check out MSDN: http://msdn.microsoft.com/en-us/library/ms403279.aspx