3.2.3.3、结论：程序判断struct里面所有字段的值，如果全部相等，返回true；否则，返回false。

3.2.4、复杂结构体(有值类型、引用类型，重写Equal函数 and 运算符'==')

3.2.4.1、测试代码：

    public struct ValPoint
    {
        public double x;
        public double y;
        public double z;

        public ValPoint(double X, double Y, double Z)
        {
            this.x = X;
            this.y = Y;
            this.z = Z;
        }
        
        public static bool operator ==(ValPoint left, ValPoint right)
        {
            return left.x == right.x;
        }

        public static bool operator !=(ValPoint left, ValPoint right)
        {
            return left.x != right.x;
        }
    }

    public class RefPoint
    {
        public double x;
        public double y;
        public double z;

        public RefPoint(double X, double Y, double Z)
        {
            this.x = X;
            this.y = Y;
            this.z = Z;
        }
    }

    public struct ValLine
    {
        public ValPoint vPoint;       // 值类型成员

        public RefPoint rPoint;       // 引用类型成员

        public ValLine(ValPoint vPoint, RefPoint rPoint)
        {
            this.vPoint = vPoint;
            this.rPoint = rPoint;
        }

        public override bool Equals(Object obj)
        {
            if (!(obj is ValLine))
            {
                return false;
            }

            if (((ValLine)obj).vPoint == this.vPoint)
            {
                return true;
            }

            return false;
        }

        public bool Equals(ValLine obj)
        {
            if (obj.vPoint == this.vPoint)
            {
                return true;
            }

            return false;
        }

        public static bool operator ==(ValLine left, ValLine right)
        {
            return left.vPoint == right.vPoint;
        }

        public static bool operator !=(ValLine left, ValLine right)
        {
            return left.vPoint != right.vPoint;
        }
    }


    ValPoint vPoint = new ValPoint(1, 2, 3);
    ValPoint vPoint2 = new ValPoint(1, 2, 3);
    ValPoint vPoint3 = new ValPoint(10, 20, 30);
    RefPoint rPoint = new RefPoint(4, 5, 6);
    RefPoint rPoint2 = new RefPoint(7, 8, 9);

    ValLine p1 = new ValLine(vPoint, rPoint);
    ValLine p2 = p1;

    p2.vPoint = vPoint2;
    Console.WriteLine(p1 == p2); //返回true
    Console.WriteLine(p1.Equals(p2)); //返回true
    Console.WriteLine(p1.Equals((object)p2)); //返回true

    p2 = p1;
    p2.vPoint = vPoint3;
    Console.WriteLine(p1 == p2); //返回true
    Console.WriteLine(p1.Equals(p2)); //返回false
    Console.WriteLine(p1.Equals((object)p2)); //返回false

    p2 = p1;
    p2.rPoint = rPoint2;
    Console.WriteLine(p1 == p2); //返回true
    Console.WriteLine(p1.Equals(p2)); //返回true
    Console.WriteLine(p1.Equals((object)p2)); //返回true

3.2.4.2、结论：此时程序执行我们重写的Equal函数 and 运算符'=='。

3.2.5、复杂结构体(内部值类型、引用类型，不重写Equal函数 and 运算符'==')

3.2.5.1、测试代码：