C＃从辅助静态类中的静态方法调用父类的实例方法

Question

I have a public class B that inherits from a class A. Class B has access to an instance method TMA(). The method TMA() is implemented in class A, and I do not have access to A. I have a secondary static class C that implements a static method GetValue(). I need to access the instance method TMA() via the static GetValue() method. One complication is that the method GetValue() gets called many times.

public class B : A
{
    ...
}

public static class C
{
    public static double GetValue()
    {
        double result = 0;
        result = TMA(); // <--- I would like to do this but it does not work.
        return result;
    }
}

I have tried the following, and although it compiles, it crashes the program on execution. It may be that the program is creating too many instances of the class B, but I am not sure.

public static class C
{
    public static double GetValue()
    {
        B b = new B();
        double result = 0;
        result = b.TMA(); // <--- This did not work.
        return result;
    }
}

I have also tried accessing the instance method TMA() via object reference, but that did not work.

public static class C
{
    public static double GetValue(..., B ob)
    {
        double result = 0;
        result = ob.TMA(); // <--- This did not work.
        return result;
    }
}

I have read about the singleton pattern but I do not see how that could help me. Any suggestions or advice would be greatly appreciated. Thank you.

Answer 1

Can you keep a static instance of B and just use it?

public static class C
{
    static B _theB = new B();

    public static double GetValue()
    {
        double result = 0;
        result = _theB.TMA(); 
        return result;
    }
}

Answer 2

Wht exaactly is TMA doing? Does it involve a particular A (or B) object?

Your third attempt would appear to be the most correct (depending on how you call) GetValue() . but it would be helpful to know exactly how it "did not work.". (Did it crash? fail to compile? What was the error message?)