.NET, C#, Reflection: list the fields of a field that, itself, has fields

Question

In .NET & C#, suppose ClassB has a field that is of type ClassA. One can easily use method GetFields to list ClassB\'

Answer 1

Use the FieldInfo.FieldType to reflect over the type of the fields in your class. E.g.

fieldInfo.FieldType.GetFields();

Here is a complete sample based on your code that uses recursion in case you have ClassZ inside ClassA. It breaks if you have a cyclic object graph.

using System;
using System.Reflection;

class ClassA {
  public byte b;
  public short s; 
  public int i;
}

class ClassB {
  public long l;
  public ClassA x;
}

class MainClass {

  public static void Main() {
    ClassB myBObject = new ClassB();
    WriteFields(myBObject.GetType(), 0);
  }

  static void WriteFields(Type type, Int32 indent) {
    foreach (FieldInfo fieldInfo in type.GetFields(BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic)) {
      Console.WriteLine("{0}{1}\t{2}", new String('\t', indent), fieldInfo.FieldType.Name, fieldInfo.Name);
      if (fieldInfo.FieldType.IsClass)
        WriteFields(fieldInfo.FieldType, indent + 1);
    }
  }

}