如何从lambda表达式中提取自定义属性值？

// 假设我们有一个自定义属性
[AttributeUsage(AttributeTargets.Method)]
public class MyCustomAttribute : Attribute
{
    public string CustomValue { get; set; }

    public MyCustomAttribute(string value)
    {
        CustomValue = value;
    }
}

// 应用自定义属性到一个方法
public class MyClass
{
    [MyCustom("Hello, World!")]
    public void MyMethod()
    {
        // ...
    }
}

// 使用反射获取属性值
var methodInfo = typeof(MyClass).GetMethod("MyMethod");
var attribute = methodInfo.GetCustomAttribute<MyCustomAttribute>();
if (attribute != null)
{
    Console.WriteLine(attribute.CustomValue); // 输出: Hello, World!
}

using System;
using System.Linq.Expressions;
using System.Reflection;

public class Program
{
    [MyCustom("Hello from Lambda!")]
    public static void Main()
    {
        Expression<Action> lambda = () => MyMethodWithAttribute();

        var methodCallExpression = (MethodCallExpression)lambda.Body;
        var methodInfo = methodCallExpression.Method;

        var attribute = methodInfo.GetCustomAttribute<MyCustomAttribute>();
        if (attribute != null)
        {
            Console.WriteLine(attribute.CustomValue); // 输出: Hello from Lambda!
        }
    }

    [MyCustom("Hello, World!")]
    public static void MyMethodWithAttribute()
    {
        // ...
    }
}