How to fix 'Cannot load dynamically generated serialization assembly' error - sql-server

Question

"Cannot load dynamically generated serialization assembly." error when executing a clr function that calls a web service in SQL server 2008 R2.
I have a database project in Visual Studio 2017 which includes a clr function that calls a web service.
The project properties include the following:
Project Settings Target Platform = SQL Server 2008
SQLCLR Target framework = .Net Framework 3.5
SQLCLR Build Generate serialization assembly = On
The serialization assembly is created in the database by a post-deployment script when the database is published.
When I publish the databse to a SQL Server 2008R2 instance on my Windows 10 PC, executing the clr function results in the "Cannot load dynamically generated serialization assembly" error, however, when the database is published to a SQL2016 instance on my PC, it runs OK
Post deployment script to register serialization assembly:
CREATE ASSEMBLY [CifasEdit.XmlSerializers] FROM 'C:\tfs\CIFAS\Source\Database\Hub\CifasEdit\CifasEdit\bin\Release\CifasEdit.XmlSerializers.dll'
WITH PERMISSION_SET = EXTERNAL_ACCESS;
GO
The full error is here
A .NET Framework error occurred during execution of user-defined routine or aggregate "xxx":
System.InvalidOperationException: Cannot load dynamically generated serialization assembly. In some hosting environments assembly load functionality is restricted, consider using pre-generated serializer. Please see inner exception for more information. ---> System.IO.FileLoadException: LoadFrom(), LoadFile(), Load(byte[]) and LoadModule() have been disabled by the host.
System.IO.FileLoadException:
at System.Reflection.Assembly.nLoadImage(Byte[] rawAssembly, Byte[] rawSymbolStore, Evidence evidence, StackCrawlMark& stackMark, Boolean fIntrospection)
at System.Reflection.Assembly.Load(Byte[] rawAssembly, Byte[] rawSymbolStore, Evidence securityEvidence)
at Microsoft.CSharp.CSharpCodeGenerator.FromFileBatch(CompilerParameters options, String[] fileNames)
at Microsoft.CSharp.CSharpCodeGenerator.FromSourceBatch(CompilerParameters options, String[] sources)
at Microsoft.CSharp.CSharpCodeGenerator.System.CodeDom.
...
System.InvalidOperationException:
at System.Xml.Serialization.Compiler.Compile(Assembly parent, String ns, XmlSerializerCompilerParameters xmlParameters, Evidence evidence)
at System.Xml.Serialization.TempAssembly.GenerateAssembly(XmlMapping[] xmlMappings, Type[] types, String defaultNamespace, Evidence evidence, XmlSerializerCompilerParameters parameters, Assembly assembly, Hashtable assemblies)
at System.Xml.Serialization.TempAssembly..ctor(XmlMapping[] xmlMappings, Type[] types, String defaultNamespace, String location, Evidence evidence)
at System.Xml.Serialization.XmlSerializer.GetSerializersFromCache(XmlMapping[] mappings, Type type)
at System.Xml.Serialization.XmlSerializer.FromMappings(XmlMapping[] mappings, Type type)
at System.Web.Services.Protocols.SoapClientType..ctor(Type type)
at System.Web.Services.Protocols.SoapHttpClientProtocol..ctor()

Answer 1

So it appears that the serialization assembly generated automatically by VS2017 does not play nice with SQL Server 2008 R2 although it works fine with SQL2016.
To get the CLR function working in 2008R2 I moved the CLR code to a separate project and generated the serialization assembly manually using sgen.exe, then registered both dlls.
Be sure to use a version of sgen for clr2.0, on my PC this was located in
C:\Program Files (x86)\Microsoft SDKs\Windows\v7.0A\bin
The command to generate the serialization assembly is
sgen.exe c:\YourDir\YourAssembly.dll
This will create an assembly called YourAssembly.XmlSerializers.dll
Register both assemblies with SQL Server:
CREATE ASSEMBLY [YourAssembly] FROM 'c:\YourDir\YourAssembly.dll' WITH PERMISSION_SET = EXTERNAL_ACCESS
CREATE ASSEMBLY [YourAssembly.XmlSerializers] FROM 'c:\YourDir\YourAssembly.XmlSerializers.dll' WITH PERMISSION_SET = SAFE