C#如何在派生类中添加属性设置器?

问题描述

我有一个要求，我必须有许多类都是从单个基类派生的.基类包含子类列表，这些子类也从相同的基类派生.

I have a requirement where I have a number of classes all derived from a single base class. The base class contains lists of child classes also derived from the same base class.

所有类都必须能够获取特定的值，这些值可以从类本身获取-或者-它是父类，具体取决于派生类是什么.

All classes need to be able to obtain specific values which may be obtained from the class itself -OR- it's parent depending on what the derived class is.

我看过使用方法而不是属性，但是我还想使这些值可用于.NET报告组件，该组件可直接访问报告引擎中公开的公共属性，因此不包括方法的使用.

I looked at using Methods rather than properties however I also want to make the values available to a .NET reporting component which directly accesses exposed public properties in the reporting engine so this excludes the use of methods.

我的问题是，在BaseClass中没有公开可用的setter的情况下，在DerivedClass中实现setter的最佳实践"方法是什么?

My question is what would be the 'best practices' method of implementing a setter in DerivedClass without having a publicly available setter in BaseClass

public class BaseClass
{
  private BaseClass _Parent;
  public virtual decimal Result
  {
    get { return ((_Parent != null) ? _Parent.Result : -1); } 
  }
}

public class DerivedClass : BaseClass
{
  private decimal _Result;
  public override decimal Result
  {
      get { return _Result; }
      // I can't use a setter here because there is no set method in the base class so this throws a build error
      //set { _Result = value;  }
  }
}

由于无法在DerivedClass中更改访问修饰符，因此无法在BaseClass中添加受保护的setter(如下所示).

I can't add a protected setter (as follows) in BaseClass as I cannot change access modifiers in DerivedClass.

public class BaseClass
{
  private BaseClass _Parent;
  public virtual decimal Result {
    get { return ((_Parent != null) ? _Parent.Result : -1); } 
    protected set { }
  }
}

public class DerivedClass : BaseClass
{
  private decimal _Result;
  public override decimal Result
  {
    get { return _Result; }
    // This setter throws a build error because of a change of access modifiers.
    //set { _Result = value; }
  }
}

我不想在带有Setter的BaseClass中添加成员变量，因为我不希望能够从BaseClass或其他从base派生的类中设置属性.

I don't want to add a member variable in BaseClass with a setter as I do not want the ability to set the property from the BaseClass or other classes that derive from base.

public class BaseClass
{
  private BaseClass _Parent;
  protected Decimal _Result; // This could result in a lot of unnecessary members in BaseClass.

  public virtual decimal Result {
    get { return _Result; } 
    // Empty setter ahead :) This does nothing.
    // I could also throw an exception here but then issues would not be found until runtime
    // and could cause confusion in the future with new developers etc.
    set { }
  }
}

public class DerivedClass : BaseClass
{
  public override decimal Result
  {
    get { return base.Result; }
    set { base._Result = value; }
  }
}

其他建议?

推荐答案

您可以使用'new'关键字，但这将替换属性，而覆盖则无法实现所需的属性.

You can use the 'new' keyword but this will replace property, what you want is not possible with override.

public class BaseClass
{
    private BaseClass _Parent;
    public virtual decimal Result
    {
        get { return ((_Parent != null) ? _Parent.Result : -1); }
    }
}

public class DerivedClass : BaseClass
{
    private decimal _Result;
    public new decimal Result
    {
        get { return _Result; }
        set { _Result = value;  }
    }
}

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