Module Module1

    Sub Main()

        Dim vb As New Microsoft.VisualBasic.VBCodeProvider
        Dim params As New CodeDom.Compiler.CompilerParameters
        params.GenerateInMemory = True
        params.GenerateExecutable = False
        params.ReferencedAssemblies.Add("System.dll")

        Dim src As String = "Imports System.Math" & vbNewLine
        src &= "Class Test" & vbNewLine
        src &= "Public Function Eval() AS Double" & vbNewLine
        src &= "Return Cos(123)" & vbNewLine
        src &= "End Function" & vbNewLine
        src &= "End Class"

        Dim risp As System.CodeDom.Compiler.CompilerResults = vb.CompileAssemblyFromSource(params, src)

        Dim inst = risp.CompiledAssembly.CreateInstance("Test")
        Dim m As Reflection.MethodInfo = inst.GetType.GetMethod("Eval")
        Console.WriteLine(m.Invoke(inst, Nothing))
        Console.ReadLine()
    End Sub

End Module