How to get instance reference

Question

Hy

I have a class like this:
public class myClass
{
public string fieldA;
public Datatime fieldB;
...
}

I would like to be able to provide a property kind of like this:
public List<object> Fields
{
          get
          {
                }
        }

that returns the actual fields of the instance - not "just" the value.

I can enumerate them using reflection, but I cannot seem to get from the FieldInfo object to the actual fueld on the instance.
The class is not sealed and I would like my Fields property to return the fields added in inherited classes also - if possible.

any feedback on how to proceed?

Best regards

Poul Lindholm Christiansen

Vulpes · Answer

If you can clarify a bit more what you are looking for I might still be able to help.

Poul Christiansen · Answer

Hi - not quite what I was looking for but it did give me an Idea - i'll tryto follow tht idea a little - thank you so far....

Vulpes · Answer

You could set fields on the actual instance as follows: using System; using System.Collections.Generic; using System.Reflection; public class FieldValuePair { public string Name {get; private set;} public object Value {get; private set;} public FieldValuePair(string name object value) { Name = name; Value = value; } public override string ToString() { return String.Format({0} = {1} Name Value); } } public class MyParentClass { protected int fieldC; public MyParentClass(int c) { fieldC = c; } } public class MyClass : MyParentClass { public string fieldA; public DateTime fieldB; public MyClass(string a DateTime b int c) : base(c) { fieldA = a; fieldB = b; } public List Fields { get { List list = new List (); BindingFlags bf = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic; Type t = typeof(MyClass); FieldInfo[] fia = t.GetFields(bf); foreach(FieldInfo fi in fia) { FieldValuePair fvp = new FieldValuePair(fi.Name fi.GetValue(this)); list.Add(fvp); } return list; } set { BindingFlags bf = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic; Type t = typeof(MyClass); foreach(FieldValuePair fvp in value) { FieldInfo fi = t.GetField(fvp.Name bf); if (fi != null) fi.SetValue(this fvp.Value); } } } } class Program { static void Main() { MyClass mc = new MyClass(Hello DateTime.Now 42); foreach(FieldValuePair fvp in mc.Fields) { Console.WriteLine(fvp); } Console.WriteLine(); List list = new List (); FieldValuePair fvpA = new FieldValuePair(fieldAGoodbye); list.Add(fvpA); mc.Fields = list; foreach(FieldValuePair fvp in mc.Fields) { Console.WriteLine(fvp); } Console.ReadKey(); } }

Poul Christiansen · Answer

If I were to assign values to the fields using your approach - then that value would only be stored in the list - not on the instance of the class - is that correct? What would i need to do if i wanted it to update the field where the value came from on the instance?

Vulpes · Answer

I'm not sure what you mean by the field itself unless you mean the FieldInfo object which is the field's representation in metadata. Fields theselves are just slots within an object's memory allocation on the heap which contain the current value of that field for that object.

Poul Christiansen · Answer

if i read your code correct - then this would give me access to the name and value of each field but not the field itself. I can now see that I need to write further requirements: using a foreach (object f in Fields) I need to also be able to assign values that would the also affect the value on the class instance. I'm sorry I didn't put that in my first question.

Vulpes · Answer

Try the following: using System; using System.Collections.Generic; using System.Reflection; public class FieldValuePair { public string Name {get; private set;} public object Value {get; private set;} public FieldValuePair(string name object value) { Name = name; Value = value; } public override string ToString() { return String.Format({0} = {1} Name Value); } } public class MyParentClass { protected int fieldC; public MyParentClass(int c) { fieldC = c; } } public class MyClass : MyParentClass { public string fieldA; public DateTime fieldB; public MyClass(string a DateTime b int c) : base(c) { fieldA = a; fieldB = b; } public List Fields { get { List list = new List (); BindingFlags bf = BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic; Type t = typeof(MyClass); FieldInfo[] fia = t.GetFields(bf); foreach(FieldInfo fi in fia) { FieldValuePair fvp = new FieldValuePair(fi.Name fi.GetValue(this)); list.Add(fvp); } return list; } } } class Program { static void Main() { MyClass mc = new MyClass(Hello DateTime.Now 42); foreach(FieldValuePair fvp in mc.Fields) { Console.WriteLine(fvp); } Console.ReadKey(); } }