从类中获取与类实例关联的属性

Question

假设我们有两个类：

MainClass:

public class MainClass
{
    [CustomAttribute("John Smith", 55)]
    ItemClass ic = new ItemClass();
}

ItemClass:

public class ItemClass
{
    public void TestMethod()
    {
        // I want to get the "John Smith" and 55 from here
    }
}

还有一个自定义属性CustomAttribute：

public class CustomAttribute : Attribute
{
    public string Name;
    public int Age;

    public CustomAttribute(string name, string age)
    {
        this.Name = name;
        this.Age = age;
    }
}

有什么方法可以从我的 ItemClass 的实例中获取该属性（在 MainClass 中定义）？

换句话说，我怎样才能从TestMethod()内部得到"John Smith"和55？

Answer 1

应该像这样工作（未经测试）：

public class ItemClass
{
    public void TestMethod()
    {
        // I want to get the "John Smith" and 55 from here
        CustomAttribute ca = typeof(MainClass)
            .GetField("ic", BindingFlags.Private | BindingFlags.Instance)
            .GetCustomAttributes(typeof(CustomAttribute), false)
            .FirstOrDefault() as CustomAttribute;

        Console.WriteLine("Name: {0}, Age: {1}", ca.Name, ca.Age);
    }
}