Property hiding and reflection (C#)

Question

Declaring a property in a derived class that matches the name of a property in the base class \"hides\" it (unless it overrides it with the override keyword).

Answer 1

GetProperties is defined as all public properties of the type.

You could get their get and set methods using:

typeof(C).GetMethods()
         .Where(m => m.Name.StartsWith("set_") || m.Name.StartsWith("get_"))

Although this seems like a bad idea, compared to going down the inheritance hierarchy to get the properties.

Answer 2

I do not think it is possible without traversing the inheritance hierarchy. It does not have to be too much code, though:

    public static IEnumerable<PropertyInfo> GetAllProperties(Type t)
    {
        while (t != typeof(object))
        {
            foreach (var prop in t.GetProperties(BindingFlags.DeclaredOnly | BindingFlags.Public | BindingFlags.Instance))
                yield return prop;
            t = t.BaseType;
        }
    }

Of course, if you know a common basetype you can stop at, instead of object, it will be more efficient. Also; it will take some time to do the reflection, so cache the result. After all, the type information won't change during execution.

Answer 3

Through reflection, the new keyword only hides the inherited property if the signature matches. I guess reflection matches signatures on property accessors (get_ & set_). It's the reasons why GetProperties() returns B.P and C.P when the return type differ.

I recently discovered Fasteflect which provides advanced reflection mechanisms.

I checked and Fasteflect type.Properties returns all the tree of hidden members (P). I think the API consider backing members (virtual/override) and hidden members (new) differently which is a good thing for your 'problem' ;)

My test with fasterflect :

class Class1
{
    public object field1 = null;

    public virtual object Property1 { get; set; }

    public object Property2 { get; set; }

    public string Property3 { get; set; }
}

class Class2 : Class1
{
    public new object field1 = null;

    public override object Property1 { get; set; }

    public new string Property3 { get; set; }
}

class Class3 : Class2
{
    public new string Property3 { get; set; }
}

Filter backing members but returns all hidden members :

typeof(Class3).Properties(Flags.ExcludeBackingMembers | Flags.Public | Flags.Instance) 

• typeof(Class3).Properties(Flags.ExcludeBackingMembers | Flags.Public | Flags.Instance) Count = 5 System.Collections.Generic.IList
  • [0] {System.String Property3} System.Reflection.PropertyInfo
  • [1] {System.Object Property1} System.Reflection.PropertyInfo
  • [2] {System.String Property3} System.Reflection.PropertyInfo
  • [3] {System.Object Property2} System.Reflection.PropertyInfo
  • [4] {System.String Property3} System.Reflection.PropertyInfo