Why does C# take value from overridden property instead of the overriding property?

Question

I would suspect the code below to output:

(I am a SmartForm object and using the method in SmartForm).xml

instead, however, it outputs:

(I am a SmartForm object and using the method in Item).xml

Why is that? How can I force C# to take the value from the overriding property? That is why I am overriding the property.

using System;

namespace TestInhersdk234
{
    public class Program
    {
        static void Main(string[] args)
        {
            SmartForm smartForm = new SmartForm();
            Console.ReadLine();
        }
    }

    public class SmartForm : Item
    {
        public SmartForm()
        {
            Console.WriteLine(FullXmlDataStorePathAndFileName);
        }

        public new string GetItemTypeIdCode
        {
            get
            {
                return String.Format("(I am a {0} object and using the method in SmartForm)", this.GetType().Name);
            }
        }
    }

    public class Item
    {
        public string FullXmlDataStorePathAndFileName
        {
            get
            {
                return GetItemTypeIdCode + ".xml";
            }
        }

        public string GetItemTypeIdCode
        {
            get
            {
                return String.Format("(I am a {0} object and using the method in Item)", this.GetType().Name);
            }
        }
    }
}

Answer 1

You need to add the override keyword to the overriding method?

Answer 2

You're not actually overriding. You're hiding. To override:

class MyBase
{
    public virtual void foo() {}
}

class MyClass : MyBase
{
    public override void foo() {}
}

Answer 3

Item's properties which you wish to override are not marked virtual. As a result, when you redefine them in SmartForm, you are merely "hiding" them, and not actually overriding them. (Additionally, you will need the override keyword in SmartForm as well.)

Check out this guide.

Answer 4

GetItemTypeIdCode isn't virtual; you're not overriding it, you're just hiding it. In that case, which method gets executed isn't based on the dynamic type of the object, but on the static type of the object reference. Inside FullXmlDataStorePathAndFileName, the static type of 'this' is Item, not SmartForm, so the Item implementation of GetItemTypeIdCode is called.

Answer 5

the property in the base class should be marked virtual

also the property in the inherited class should be marked overrides

also i am not sure why the keyword new appears in your code in the property definition