LINQ Extensions not available inside CSharpCodeProvider - linq

Question

I have a .NET application that can take a script written in C# and executes it internally. The scripts are parsed by the class listed below and then compiled. I find that whenever I try and use System.Xml.Linq in the C# script that is compiled I get a compile error and I am not sure why.
public static void CreateFunction(string scriptCode, BO.ObjectBO obj)
{
CSharpCodeProvider provider = new CSharpCodeProvider();
CompilerParameters options = new CompilerParameters();
options.ReferencedAssemblies.Add("System.Data.dll");
options.ReferencedAssemblies.Add("System.dll");
options.ReferencedAssemblies.Add("System.Xml.dll");
options.ReferencedAssemblies.Add("System.Linq.dll");
options.ReferencedAssemblies.Add("System.Xml.Linq.dll");
options.GenerateExecutable = false;
options.GenerateInMemory = true;
CompilerResults results = provider.CompileAssemblyFromSource(options, scriptCode);
_errors = results.Errors;
if (results.Errors.HasErrors)
{
DataTable errorTable = BO.DataTableBO.ErrorTable();
foreach(CompilerError err in results.Errors)
{
DataRow dr = errorTable.NewRow();
dr["ErrorMessage"] = "Line "+ err.ErrorNumber.ToString() + " " + err.ErrorText;
errorTable.Rows.Add(dr);
}
return;
}
Type binaryFunction = results.CompiledAssembly.GetType("UserFunctions.BinaryFunction");
_methodInfo = binaryFunction.GetMethod("Function");
}
Here is the error message I get when I try and run a script that makes use of LINQ extensions inside the compiler.
'System.Collections.Generic.IEnumerable<System.Xml.Linq.XElement>' does not contain a definition for 'Select' and no extension method 'Select' accepting a first argument of type 'System.Collections.Generic.IEnumerable<System.Xml.Linq.XElement>' could be found (are you missing a using directive or an assembly reference?)
Does anyone see what I may be doing wrong? I am attempting to include System.Linq and System.Xml.Linq yet the compiler does not seem to be able to locate them.
Here is an example C# script I am trying to compile that makes use of LINQ extensions.
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Xml.Linq;
namespace CompilerTest
{
public class BinaryFunction
{
public static void Function()
{
string xmlData = #"<data>
<clients>
<client>
<clientId>1</clientId>
<clientName>Dell</clientName>
</client>
<client>
<clientId>2</clientId>
<clientName>Apple</clientName>
</client>
</clients>
</data>";
XDocument xDoc = XDocument.Parse(xmlData);
List<string> results = xDoc.Descendants("data")
.Descendants("client")
.Select(x => x.Element("clientName").Value)
.ToList<string>();
}
}
}
UPDATE: I confirmed that the following assemblies were in the GAC. System.Xml and System.Xml.Linq. I also added the compiler version to the constructor and I still get the same error.
CSharpCodeProvider(new Dictionary<String, String> { { "CompilerVersion", "v4.6.1" } })

Answer 1

After searching for related errors I found the solution. I needed to add System.Core as a referenced assembly.
options.ReferencedAssemblies.Add("System.Core.dll");
Once I did this then the LINQ assemblies were used and I was able to use LINQ extensions. So to be clear my new code is
CSharpCodeProvider provider = new CSharpCodeProvider();
CompilerParameters options = new CompilerParameters();
options.ReferencedAssemblies.Add("System.Data.dll");
options.ReferencedAssemblies.Add("System.dll");
options.ReferencedAssemblies.Add("System.Xml.dll");
options.ReferencedAssemblies.Add("System.Linq.dll");
options.ReferencedAssemblies.Add("System.Xml.Linq.dll");
options.ReferencedAssemblies.Add("System.Core.dll");
I am not sure why the reference to System.Core.dll is needed to be added as I would assume that it was referenced by default when creating a compiler instance but I guess not.