InjectedMethodInfo

InjectedMethodInfo.cs

    internal sealed class InjectedMethodInfo
    {
        public readonly MethodInfo MethodInfo;
        public readonly ParameterInfo[] Parameters;
        public readonly Action<object, object[]> Call;

        public InjectedMethodInfo(MethodInfo methodInfo)
        {
            MethodInfo = methodInfo;
            Parameters = methodInfo.GetParameters();
            Call = GenerateCall(methodInfo);
        }

        private static Action<object, object[]> GenerateCall(MethodInfo methodInfo)
        {
            var instance = Expression.Parameter(typeof(object), "instance");
            var arguments = Expression.Parameter(typeof(object[]), "arguments");
            var instanceCast = Expression.Convert(instance, methodInfo.DeclaringType!);
            var methodParams = methodInfo.GetParameters();
            var argumentExpressions = new Expression[methodParams.Length];
            
            for (int i = 0; i < methodParams.Length; i++)
            {
                var index = Expression.ArrayIndex(arguments, Expression.Constant(i));
                argumentExpressions[i] = Expression.Convert(index, methodParams[i].ParameterType);
            }
            
            var callExpression = (Expression) Expression.Call(instanceCast, methodInfo, argumentExpressions);
            var expression = Expression.Lambda<Action<object, object[]>>(callExpression, instance, arguments);
            return expression.Compile();
        }
    }