C#中如何使用反射和元数据处理代码生成和扩展

using System;
using System.Reflection;
using Microsoft.CSharp;

namespace CodeGeneration
{
    public class CodeGenerator
    {
        public static Type GenerateClass(string className)
        {
            // 创建编译器
            CSharpcodeProvider codeProvider = new CSharpCodeProvider();
            ICodeCompiler codeCompiler = codeProvider.CreateCompiler();

            // 创建编译参数
            CompilerParameters compilerParams = new CompilerParameters();
            compilerParams.GenerateInMemory = true;
            compilerParams.GenerateExecutable = false;

            // 创建代码
            string code = "public class " + className + " { public void SayHello() { Console.WriteLine("Hello, Reflection"); } }";

            // 编译代码
            CompilerResults compilerResults = codeCompiler.CompileAssemblyFromSource(compilerParams, code);

            // 获取生成的程序集
            Assembly assembly = compilerResults.CompiledAssembly;

            // 获取生成的类类型
            Type classType = assembly.GetType(className);

            return classType;
        }
    }

    public class Program
    {
        public static void Main(string[] args)
        {
            Type dynamicClassType = CodeGenerator.GenerateClass("DynamicClass");
            object dynamicClassInstance = Activator.CreateInstance(dynamicClassType);
            MethodInfo sayHelloMethod = dynamicClassType.GetMethod("SayHello");
            sayHelloMethod.Invoke(dynamicClassInstance, null);
        }
    }
}

using System;
using System.Reflection;

namespace Extension
{
    public static class StringExtensions
    {
        public static string Reverse(this string str)
        {
            char[] charArray = str.ToCharArray();
            Array.Reverse(charArray);
            return new string(charArray);
        }
    }

    public class Program
    {
        public static void Main(string[] args)
        {
            string str = "Hello, World!";
            MethodInfo reverseMethod = typeof(string).GetMethod("Reverse", Type.EmptyTypes);
            string reversedStr = (string)reverseMethod.Invoke(str, null);
            Console.WriteLine(reversedStr);
        }
    }
}