using System;

using System.Linq;

using System.Linq.Expressions;

​

public class Program

{

    public int TestMethod(bool arg)

    {

        Console.WriteLine("Called from compiled expression");

        return arg ? 0 : 1;

    }

    public static Func<object, object, object> CreateLambdaExpression(string tService, string methodName)

    {

        var inputServiceType = Type.GetType(tService);

        var methodInfo = inputServiceType.GetMethod(methodName);

        var inputType = methodInfo.GetParameters().First().ParameterType;

​

        var objType = typeof(object);

        var instance = Expression.Parameter(objType, "serviceInstance");

        var input = Expression.Parameter(objType, "inputData");

        var call = Expression.Call(

            Expression.Convert(instance, inputServiceType),

            methodInfo,

            Expression.Convert(input, inputType));

        var body = Expression.Convert(call, objType);

​

        var lambdaFunc = Expression.Lambda<Func<object, object, object>>(body, instance, input).Compile(); //<= this line throws the error.

        return lambdaFunc;

    }

​

    public static void Main()

    {

        var service = new Program();

        var func = CreateLambdaExpression(typeof(Program).FullName, "TestMethod");

        var result = func(service, true);

        Console.WriteLine(result);

    }

}