Categories: C#

Dynamic C# code compilation in memory

Simple example how to compile C# code within a C#-Programm

using System;
using System.CodeDom.Compiler;
using System.Reflection;
using Microsoft.CSharp;

public static class DynamicCompilation {
    public static object CompileAndRun(string code) {
        CSharpCodeProvider codeProvider = new CSharpCodeProvider();
        CompilerParameters compilerParams = new CompilerParameters();
        compilerParams.GenerateInMemory = true;
        compilerParams.GenerateExecutable = false;

        CompilerResults results = codeProvider.CompileAssemblyFromSource(compilerParams, code);
        if (results.Errors.HasErrors) {
            string errors = "";
            foreach (CompilerError error in results.Errors) {
                errors += error.ErrorText + "\n";
            }
            throw new Exception("Compilation failed:\n" + errors);
        }

        Assembly assembly = results.CompiledAssembly;
        object instance = assembly.CreateInstance("DynamicCode");
        MethodInfo method = instance.GetType().GetMethod("Main");
        return method.Invoke(instance, null);
    }
}

Calling the code

    string code = "using System; public class DynamicCode { public static void Main() { Console.WriteLine(\"Hello World!\"); } }";
    DynamicCompilation.CompileAndRun(code);

Whitelist Assemblies

You can also define a whitelist of assemblies to use, just add them to the ReferencedAssemblies. If you dont add assemblies, the compiler gives access to all assemblies on the system!

    compilerParams.ReferencedAssemblies.Add("System.dll");
    compilerParams.ReferencedAssemblies.Add("System.Core.dll");