使用C#利用多态性写一个可以计算多种立体图形（立方体，球体，三棱锥，圆柱体)的体积和表面积，

好的，以下是一个示例代码：

using System;

namespace GeometryCalculator
{
    class Program
    {
        static void Main(string[] args)
        {
            // 创建各种立体图形的实例
            Cube cube = new Cube(5);
            Sphere sphere = new Sphere(3);
            Pyramid pyramid = new Pyramid(4, 6);
            Cylinder cylinder = new Cylinder(2, 5);

            // 计算并输出各种立体图形的体积和表面积
            Console.WriteLine("Cube: Volume={0}, Surface Area={1}", cube.Volume(), cube.SurfaceArea());
            Console.WriteLine("Sphere: Volume={0}, Surface Area={1}", sphere.Volume(), sphere.SurfaceArea());
            Console.WriteLine("Pyramid: Volume={0}, Surface Area={1}", pyramid.Volume(), pyramid.SurfaceArea());
            Console.WriteLine("Cylinder: Volume={0}, Surface Area={1}", cylinder.Volume(), cylinder.SurfaceArea());

            Console.ReadLine();
        }
    }

    // 抽象的立体图形类
    abstract class Shape
    {
        // 计算体积的抽象方法
        public abstract double Volume();

        // 计算表面积的抽象方法
        public abstract double SurfaceArea();
    }

    // 立方体类
    class Cube : Shape
    {
        private double sideLength;

        public Cube(double sideLength)
        {
            this.sideLength = sideLength;
        }

        public override double Volume()
        {
            return Math.Pow(sideLength, 3);
        }

        public override double SurfaceArea()
        {
            return 6 * Math.Pow(sideLength, 2);
        }
    }

    // 球体类
    class Sphere : Shape
    {
        private double radius;

        public Sphere(double radius)
        {
            this.radius = radius;
        }

        public override double Volume()
        {
            return (4 / 3.0) * Math.PI * Math.Pow(radius, 3);
        }

        public override double SurfaceArea()
        {
            return 4 * Math.PI * Math.Pow(radius, 2);
        }
    }

    // 三棱锥类
    class Pyramid : Shape
    {
        private double baseLength;
        private double height;

        public Pyramid(double baseLength, double height)
        {
            this.baseLength = baseLength;
            this.height = height;
        }

        public override double Volume()
        {
            return (1 / 3.0) * Math.Pow(baseLength, 2) * height;
        }

        public override double SurfaceArea()
        {
            double slantHeight = Math.Sqrt(Math.Pow(baseLength / 2.0, 2) + Math.Pow(height, 2));
            return (baseLength * slantHeight) + (2 * Math.Pow(baseLength / 2.0, 2));
        }
    }

    // 圆柱体类
    class Cylinder : Shape
    {
        private double radius;
        private double height;

        public Cylinder(double radius, double height)
        {
            this.radius = radius;
            this.height = height;
        }

        public override double Volume()
        {
            return Math.PI * Math.Pow(radius, 2) * height;
        }

        public override double SurfaceArea()
        {
            return (2 * Math.PI * radius * height) + (2 * Math.PI * Math.Pow(radius, 2));
        }
    }
}

以上代码中，我们定义了一个抽象的立体图形类 `Shape`，其中包含了两个抽象方法 `Volume()` 和 `SurfaceArea()`，用于计算体积和表面积。然后我们分别定义了立方体类 `Cube`、球体类 `Sphere`、三棱锥类 `Pyramid` 和圆柱体类 `Cylinder`，这些类都继承自 `Shape` 类，并分别实现了其抽象方法。在 `Main` 方法中，我们创建了各种立体图形的实例，并调用了它们的 `Volume()` 和 `SurfaceArea()` 方法来计算它们的体积和表面积，并输出结果。