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只要十步，你就可以应用表达式树来优化动态调用（二）( 五 )

>(body,inputExp);return final;Expression CreateDefaultResult(){var okMethod = typeof(ValidateResult).GetMethod(nameof(ValidateResult.Ok));Debug.Assert(okMethod != null, nameof(okMethod) + " != null");var methodCallExpression = Expression.Call(okMethod);var re = Expression.Assign(resultExp, methodCallExpression);/*** final as:* result = ValidateResult.Ok()*/return re;}Expression CreateValidateStringRequiredExpression(PropertyInfo propertyInfo)=> CreateValidateExpression(propertyInfo,CreateValidateStringRequiredExp());Expression CreateValidateStringMinLengthExpression(PropertyInfo propertyInfo,int minlengthAttributeLength)=> CreateValidateExpression(propertyInfo,CreateValidateStringMinLengthExp(minlengthAttributeLength));Expression CreateValidateExpression(PropertyInfo propertyInfo,Expression validateFuncExpression){var isOkProperty = typeof(ValidateResult).GetProperty(nameof(ValidateResult.IsOk));Debug.Assert(isOkProperty != null, nameof(isOkProperty) + " != null");var convertedExp = Expression.Convert(inputExp, type);var namePropExp = Expression.Property(convertedExp, propertyInfo);var nameNameExp = Expression.Constant(propertyInfo.Name);var requiredMethodExp = Expression.Invoke(validateFuncExpression,nameNameExp,namePropExp);var assignExp = Expression.Assign(resultExp, requiredMethodExp);var resultIsOkPropertyExp = Expression.Property(resultExp, isOkProperty);var conditionExp = Expression.IsFalse(resultIsOkPropertyExp);var ifThenExp =Expression.IfThen(conditionExp,Expression.Return(returnLabel, resultExp));var re = Expression.Block(new[] {resultExp},assignExp,ifThenExp);return re;}}}catch (Exception e){Console.WriteLine(e);throw;}}[Test]public void Run(){// see code in demo repo}public static ValidateResult Validate(CreateClaptrapInput input){return ValidateFunc[typeof(CreateClaptrapInput)].Invoke(input);}}}代码要点：

  1. 将 Func 替换为了 Func ， 并且将写死的 typeof (CreateClaptrapInput) 都替换为了 type 。
  2. 将对应类型的验证器创建好之后保存在 ValidateFunc 中 。 这样就不需要每次都重建整个 Func 。
第十步 ， 加入一些细节最后的最后 ， 我们又到了令人愉快的 “加入一些细节” 阶段：按照业务特性对抽象接口和实现进行调整 。 于是我们就得到了本示例最终的版本 。
using System;using System.Collections.Concurrent;using System.Collections.Generic;using System.ComponentModel.DataAnnotations;using System.Diagnostics;using System.Linq;using System.Linq.Expressions;using System.Reflection;using Autofac;using FluentAssertions;using NUnit.Framework;using Module = Autofac.Module;// ReSharper disable InvalidXmlDocCommentnamespace Newbe.ExpressionsTests{////// Final///public class X03PropertyValidationTest10{private const int Count = 10_000;private IValidatorFactory _factory = null!;[SetUp]public void Init(){try{var builder = new ContainerBuilder();builder.RegisterModule();var container = builder.Build();_factory = container.Resolve();}catch (Exception e){Console.WriteLine(e);throw;}}[Test]public void Run(){for (int i = 0; i


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