Overriding an automatic property

c#

Solution

Short Answer: Yes, the `Child` allocates all `Base` class fields, so it still has the backing field allocated. However, you can't access it any other way than through `Base.MyInt` property.

Long Answer:

Quick disassembly results.

`Base` and `Child` classes implementation:

public class Base
{
    public virtual int MyInt { get; set; }
}

public class Child : Base
{
    private int anotherInt;

    public override int MyInt
    {
        get { return anotherInt; }
        set { anotherInt = value; }
    }
}

As you can see, the backing field exists within `Base` class. However, it is private, so you can't access it from `Child` class:

.field private int32 '<MyInt>k__BackingField'

And your `Child.MyInt` property does not use that field. The property IL is:

.method public hidebysig specialname virtual 
    instance int32 get_MyInt () cil managed 
{
    // Method begins at RVA 0x2109
    // Code size 7 (0x7)
    .maxstack 8

    IL_0000: ldarg.0
    IL_0001: ldfld int32 ConsoleApplication2.Child::anotherInt
    IL_0006: ret
} // end of method Child::get_MyInt

.method public hidebysig specialname virtual 
    instance void set_MyInt (
        int32 'value'
    ) cil managed 
{
    // Method begins at RVA 0x2111
    // Code size 8 (0x8)
    .maxstack 8

    IL_0000: ldarg.0
    IL_0001: ldarg.1
    IL_0002: stfld int32 ConsoleApplication2.Child::anotherInt
    IL_0007: ret
} // end of method Child::set_MyInt

Is uses `anotherInt` field, as you could expect.

The only ways to access the `'<MyInt>k__BackingField'` (indirectly, through `Base.MyInt` property) are:

- `base.MyInt` from within `Child` class

Problem

since this ``` public int MyInt{ get; set;} ``` is equivalent to ``` private int _myInt; public int MyInt{ get{return _myInt;} set{_myInt = value;} } ``` when you make the automatic property virtual ``` public virtual int MyInt{ get; set;} ``` and then override this property in a child class ``` public override int MyInt{ get{return someVar;} set{someVar = value;} } ``` does this child class now have an unwelcomed and hidden allocation of _myInt?

Original source