PropertyInfo如何实现深层属性访问

在C#中，可以使用PropertyInfo类实现深层属性访问。首先，获取对象的类型信息，然后使用GetProperty方法获取指定属性的PropertyInfo对象，再递归地获取嵌套属性的PropertyInfo对象，直到达到需要访问的深层属性。

以下是一个示例代码，演示如何使用PropertyInfo实现深层属性访问：

using System;
using System.Reflection;

public class Person
{
    public string Name { get; set; }
    public Address Address { get; set; }
}

public class Address
{
    public string Street { get; set; }
    public string City { get; set; }
}

class Program
{
    static void Main()
    {
        Person person = new Person
        {
            Name = "John Doe",
            Address = new Address
            {
                Street = "123 Main St",
                City = "City"
            }
        };

        PropertyInfo propertyInfo = GetDeepPropertyInfo(person, "Address.City");
        if (propertyInfo != null)
        {
            object propertyValue = GetDeepPropertyValue(person, "Address.City");
            Console.WriteLine(propertyInfo.Name + ": " + propertyValue);
        }
    }

    static PropertyInfo GetDeepPropertyInfo(object obj, string propertyName)
    {
        Type type = obj.GetType();
        string[] propertyNames = propertyName.Split('.');

        PropertyInfo propertyInfo = null;
        foreach (string name in propertyNames)
        {
            propertyInfo = type.GetProperty(name);
            if (propertyInfo != null)
            {
                type = propertyInfo.PropertyType;
            }
            else
            {
                return null;
            }
        }

        return propertyInfo;
    }

    static object GetDeepPropertyValue(object obj, string propertyName)
    {
        Type type = obj.GetType();
        string[] propertyNames = propertyName.Split('.');

        object propertyValue = null;
        foreach (string name in propertyNames)
        {
            PropertyInfo propertyInfo = type.GetProperty(name);
            if (propertyInfo != null)
            {
                propertyValue = propertyInfo.GetValue(obj);
                obj = propertyValue;
                type = propertyInfo.PropertyType;
            }
            else
            {
                return null;
            }
        }

        return propertyValue;
    }
}

在上面的示例中，GetDeepPropertyInfo和GetDeepPropertyValue方法分别用于获取深层属性的PropertyInfo对象和属性值。通过使用这两个方法，可以实现对任意深层属性的访问。