C# 反射:在成员字段上查找属性 [英] C# Reflection : Finding Attributes on a Member Field

问题描述

我可能问错了这个问题，但是您可以/如何在其自身中找到某个类的字段...例如...

I may be asking this incorrectly, but can/how can you find fields on a class within itself... for example...

public class HtmlPart {
  public void Render() {
    //this.GetType().GetCustomAttributes(typeof(OptionalAttribute), false);
  }
}

public class HtmlForm {
  private HtmlPart _FirstPart = new HtmlPart();      
  [Optional] //<-- how do I find that?
  private HtmlPart _SecondPart = new HtmlPart();
}

或者也许我只是做错了......我怎样才能调用一个方法，然后检查应用于自身的属性?

Or maybe I'm just doing this incorrectly... How can I call a method and then check for attributes applied to itself?

另外，为了这个问题 - 我只是好奇是否可以在不知道/访问父类的情况下找到属性信息！

Also, for the sake of the question - I'm just curious if it was possible to find attribute information without knowing/accessing the parent class!

推荐答案

如果我正确理解你的问题，我认为你试图做的事情是不可能的......

If I understand your question correctly, I think what you are trying to do is not possible...

在 Render 方法中，您希望获得应用于对象的可能属性.该属性属于 _SecondPart 字段，而该属性属于 HtmlForm 类.

In the Render method, you want to get a possible attribute applied to the object. The attribute belongs to the field _SecondPart witch belongs to the class HtmlForm.

为此，您必须将调用对象传递给 Render 方法:

For that to work you would have to pass the calling object to the Render method:

    public class HtmlPart {
        public void Render(object obj) {
            FieldInfo[] infos = obj.GetType().GetFields(BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Instance);

            foreach (var fi in infos)
            {
                if (fi.GetValue(obj) == this && fi.IsDefined(typeof(OptionalAttribute), true))
                    Console.WriteLine("Optional is Defined");
            }
        }
    }

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