總結用運算式數調用的執行個體代碼

照著 利用運算式樹狀架構構建委託改善反射效能 做了一點小更改正好適合自己用

    public static class DynamicMethodBuilder    {public static Delegate BuildDynamicDelegate(MethodInfo methodInfo, ConstructorInfo constructorInfo = null)        {if (methodInfo == null)throw new ArgumentNullException("methodInfo");            List<ParameterExpression> paramExpressions = methodInfo.GetParameters().Select((p, i) =>{var name = "param" + (i + 1);return Expression.Parameter(p.ParameterType, name);            }).ToList();            MethodCallExpression callExpression;if (methodInfo.IsStatic)            {//Call(params....)callExpression = Expression.Call(methodInfo, paramExpressions);            }else{if (constructorInfo != null)                {//Instance(params).Call(params....)List<ParameterExpression> constructorParamExpressions = constructorInfo.GetParameters().Select((p, i) =>{var name = "constparam" + (i + 1);return Expression.Parameter(p.ParameterType, name);                    }).ToList();                    callExpression = Expression.Call(Expression.New(constructorInfo, constructorParamExpressions), methodInfo, paramExpressions);                    paramExpressions.InsertRange(0, constructorParamExpressions);                }else{                    callExpression = Expression.Call(Expression.New(methodInfo.ReflectedType), methodInfo, paramExpressions);                }            }return Expression.Lambda(callExpression, paramExpressions).Compile();        }     }

測試：

    public class Baby    {        private readonly DateTime _birthDay;        public Baby(DateTime birthDay)        {            _birthDay = birthDay;        }        public Baby()        {            _birthDay = DateTime.Now;        }        public string GetBabyInfo(string name, int sex) => $"姓名：{name} , 出生天數：{ DateTime.Now- _birthDay} ,性別 ：{(sex == 1 ? "男" : "女")}";    }    class Program    {        static void Main(string[] args)        {            Type targetType = Assembly.GetExecutingAssembly().GetType("ConsoleApplication1.Baby");            MethodInfo methodInfo = targetType.GetMethod("GetBabyInfo", new[] { typeof(string), typeof(int) });            ConstructorInfo constructor = targetType.GetConstructor(new[] { typeof(DateTime) });            WithConstructor(methodInfo, constructor);            WithOutConstructor(methodInfo);            Console.ReadKey();        }        static void WithConstructor(MethodInfo methodInfo, ConstructorInfo constructor)        {            var func = (Func<DateTime, string, int, string>)DynamicMethodBuilder.BuildDynamicDelegate(methodInfo, constructor);            Console.WriteLine(func(DateTime.Now.AddDays(-100), "糖墩兒", 1));        }        static void WithOutConstructor(MethodInfo methodInfo)        {            var func = (Func<string, int, string>)DynamicMethodBuilder.BuildDynamicDelegate(methodInfo);            Console.WriteLine(func("糖墩兒", 1));        }    }