使用通用基类在对象上调用受保护的方法

Question

I need to be able to access a protected property/method on an object with the common base class to the calling scope. The compiler doesn't seem to like this at all.

class Base
{
    protected int Data { get; set; }
}
class SubClasss1 : Base
{

}
class SubClasss2 :Base
{
    public SubClasss1 MyFunction() {
        SubClasss1 x = new SubClasss1();
        x.Data = this.Data; // NOT HAPPY
        return x;
    }
}

I've figured this may work, but it doesn't

((Base)copy).Data = ...

This does work but is a bit ugly

class Base
{
    protected int Data { get; set; }
    protected int GetData(Base obj) { return obj.Data; }
    protected void SetData(Base obj, int value) { obj.Data = value; }
}

class SubClasss1 : Base
{

}

class SubClasss2 : Base
{
    public SubClasss1 MyFunction()
    {
        SubClasss1 x = new SubClasss1();
        this.SetData(x, this.Data);
        return x;
    }
}

I was trying to avoid using protected internal as I don't want to clutter the public interface within the project.

Answer 1

This is because protected member can be accessed with in the derived class not outside of it. What you can do is add it to constructor like:

class SubClasss1 : Base
{
    public SubClasss1(int data)
    {
        Data = data; // can be accessed within the class but not from outside
    }
}

and then you would need to provide it:

class SubClasss2 : Base
{
    public SubClasss1 MyFunction()
    {
        SubClasss1 copy = new SubClasss1(this.Data);

        return copy;
    }
}

Answer 2

One way can be create public set method in SubClasss2 and then you should be able to read the value of it and set it into SubClass1 in your Myfucntion .

class Base
{
    protected int Data { get; set; }
    protected int GetData(Base obj) { return obj.Data; }
    protected void SetData(Base obj, int value) { obj.Data = value; }
}

class SubClasss1 : Base
{
    public void SetData(Base obj, int value) { this.Data = value; }
}

class SubClasss2 : Base
{
    public void SetData(Base obj, int value) { this.Data = value; }
    public SubClasss1 MyFunction()
    {
        SubClasss1 x = new SubClasss1();
        x.SetData(x, this.Data);
        return x;
    }
}

class Program
{
    static void Main(string[] args)
    {
        SubClasss2 subClass2Obj= new SubClasss2();
        subClass2Obj.SetData(subClass2Obj, 30);
        var subClass1Obj = subClass2Obj.MyFunction();
    }
}