我把 Dimenzije 改成了一个类而不是结构体，像这样:

I changed Dimenzije to be a class instead of struct, like this:

public class Dimenzije
{
    public Dimenzije() { }
    public Dimenzije(double d, double s, double v)
    {
        duzina = d; sirina = s; visina = v;
    }
    public double duzina{get; set;}
    public double sirina{get; set;}
    public double visina{get; set;}

}

它按预期工作.注意 Dimenzije() 构造函数的存在！

It works as expected. Notice the presence of Dimenzije() constructor!