Make readonly property in derived class

Question

I am overriding a property in my derived class that I would like to make it read-only. The C # compiler won't let me change access modifiers, so it should stay open.

What is the best way to do this? Should I just throw InvalidOperationExceptionin set { }?

Answer 1

Having setter throw InvalidOperationExceptionin a derived class violates the Liskov Subscription Principle . Essentially makes the use of the setter contextual for a base class type that substantially eliminates the meaning of polymorphism.

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class C1 { 
  public virtual int ReadOnlyProperty { get; } 
}
class C2 { 
  public sealed override int ReadOnlyProperty { 
    get { return Property; }
  }
  public int Property {
    get { ... }
    set { ... }
  }
}

, , C1 , C2

Answer 2

:

class Foo
{
    private string _someString;
    public virtual string SomeString 
    {
        get { return _someString; }
        set { _someString = value; }
    }
}

class Bar : Foo
{
    public new string SomeString 
    { 
        get { return base.SomeString; }
        private set { base.SomeString = value; }
    }
}

namespace ConsoleApplication3
{
    class Program
    {
        static void Main( string[] args )
        {
            Foo f = new Foo();
            f.SomeString = "whatever";  // works
            Bar b = new Bar();
            b.SomeString = "Whatever";  // error
        }
    }
}

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Answer 3

,

public class Aclass {        
    public int ReadOnly { get; set; }
}

public class Bclass : Aclass {        
    public new int ReadOnly { get; private set; }
}

Answer 4

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Answer 5

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Answer 6

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public class MaybeMutableFoo
{
    public string Foo {get {return Foo_get();} set {Foo_set(value);}
    protected abstract string Foo_get();
    protected abstract void Foo_set(string value};
}

ImmutableFoo :

    new public string Foo {get {return Foo_get();}

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