I need to dynamically build and run a student’s code (StudentCode.cs) from within my class (TeacherCode.cs). I’m using reflection and Roslyn for this purpose. Specifically, I want to check if StudentCode.cs contains a method named Print, and if it does, I want to invoke this method. (Later on, I also want to check if the student uses recursion, loops, among other code constructs.)

However, I am getting some errors:

Compilation failed:
(8,17): error CS0012: The type ‘Object’ is defined in an assembly that is not referenced. You must add a reference to assembly ‘System.Runtime, Version=8.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a’.
(8,9): error CS0012: The type ‘Decimal’ is defined in an assembly that is not referenced. You must add a reference to assembly ‘System.Runtime, Version=8.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a’.

Student Code:

// StudentCode.cs
using System;

public class StudentClass
{
    public static void Print()
    {
        Console.WriteLine("Hello from StudentClass.Print!");
    }
}

Teacher’s code:

// TeacherCode.cs
using System;
using System.IO;
using System.Linq;
using System.Reflection;
using Microsoft.CodeAnalysis;
using Microsoft.CodeAnalysis.CSharp;

public class Checker
{
public static void Main(string[] args)
{
// Path to the student's code file
string filePath = "StudentCode.cs";

        if (!File.Exists(filePath))
        {
            Console.WriteLine("File not found: " + filePath);
            return;
        }
    
        string studentCode = File.ReadAllText(filePath);
    
        // Check if 'Print' method exists, and if so,
        // invoke the 'Print' method
        CheckAndInvoke(studentCode, "Print");
    }
    
    static void CheckAndInvoke(string code, string methodName)
    {
        var syntaxTree = CSharpSyntaxTree.ParseText(code);
        var compilation = CSharpCompilation.Create("StudentCode",
            new[] { syntaxTree },
            new[]
            {
                MetadataReference.CreateFromFile(typeof(object).Assembly.Location),
                MetadataReference.CreateFromFile(typeof(Console).Assembly.Location),
                MetadataReference.CreateFromFile(typeof(System.Linq.Enumerable).Assembly.Location)
            },
            new CSharpCompilationOptions(OutputKind.DynamicallyLinkedLibrary));
    
        using (var ms = new MemoryStream())
        {
            var result = compilation.Emit(ms);
    
            if (!result.Success)
            {
                Console.WriteLine("Compilation failed:");
                foreach (var diagnostic in result.Diagnostics)
                {
                    Console.WriteLine(diagnostic.ToString());
                }
                return;
            }
    
            ms.Seek(0, SeekOrigin.Begin);
            var assembly = Assembly.Load(ms.ToArray());
    
            // Find the class and method
            var type = assembly.GetTypes().FirstOrDefault();
            if (type != null)
            {
                var method = type.GetMethod(methodName, BindingFlags.Static | BindingFlags.Public);
                if (method != null)
                {
                    // Invoke the Print method
                    method.Invoke(null, null);
                }
                else
                {
                    Console.WriteLine("Method 'Print' not found in compiled assembly.");
                }
            }
            else
            {
                Console.WriteLine("No classes found in the compiled assembly.");
            }
        }
    }

}