Type.GetFields返回公共字段的空System.Reflection.FieldInfo数组

Question

I have a class that contains only a number of public fields of rather standard types. The call myObject.GetType().GetFields() returns an empty array.

What can the problem be?

UPDATE: I am sorry folks, the problem was that I was using a class exposed by WCF service. The original class (say A) and the exposed (WcfReference.A) are different classes. A's members become private fields in WcfReference.A and exposed as properties.

Perhaps the question should be deleted.

Answer 1

GetFields() without arguments will return the public Fields (not properties as @Kenneth Ito noticed) of your type.

example

public class Test {
   public string var_;//I'm a public field, I'll be returned
   private int id_; //I'm a private field, you'll have to do more to get me
   public int Id {get { return id_;} set {id_=value;}} //I'm a property, I don't feel concerned
}

if you do

var test = new Test();
test.GetType().GetFields();

will return an array with one item : var_

Answer 2

In older versions of .NET (I'm adding functionality to a 1.1 project, pity me), the default method GetFields() will return an empty array. After 1.1, they updated this method to include all public properties. I don't know why they made this change, as there is already a GetProperties() method which will do the same thing.

This method is the way to get at private fields, so knowledge of how to work with it is critical. There is an overload for the method GetFields(BindingFlags flags) . This uses a combination of BindingFlags to determine which fields you want from your object.

So if you want instance private fields, you would call:

GetFields(BindingFlags.Instance | BindingFlags.NonPublic);

If you only want public static properties, you would call:

GetFields(BindingFlags.Static | BindingFlags.Public);

You can also continue to combine them for all static fields:

GetFields(BindingFlags.Static | BindingFlags.Public | BindingFlags.NonPublic);

There are many other types of BindingFlags , so check out the MSDN page linked above for any others you might need.