您可以声明您的子类可以覆盖的实例级抽象方法：
public abstract class Vector
{
protected abstract Vector Add(Vector otherVector);
public static Vector operator +(Vector v1, Vector v2)
{
return v1.Add(v2);
}
}
public class SubVector : Vector
{
protected override Vector Add(Vector otherVector)
{
//do some SubVector addition
}
}
可能会遇到一些问题，尤其是对于多个子类（SubVector 是否必须知道如何添加 SomeOtherSubVectorClass？如果添加 ThirdVectorType 类会怎样？）并且可能处理空情况。此外，确保SubVector.Add 在交换操作方面的行为与SomeOtherSubVectorClass.Add 相同。
编辑：根据您的其他 cmets，您可以这样：
public class Vector2D : Vector
{
public double X { get; set; }
public double Y { get; set; }
protected override Vector Add(Vector otherVector)
{
Vector2D otherVector2D = otherVector as Vector2D;
if (otherVector2D != null)
return new Vector2D() { X = this.X + otherVector2D.X, Y = this.Y + otherVector2D.Y };
Vector3D otherVector3D = otherVector as Vector3D;
if (otherVector3D != null)
return new Vector3D() { X = this.X + otherVector3D.X, Y = this.Y + otherVector3D.Y, Z = otherVector3D.Z };
//handle other cases
}
}
public class Vector3D : Vector
{
public double X { get; set; }
public double Y { get; set; }
public double Z { get; set; }
protected override Vector Add(Vector otherVector)
{
Vector2D otherVector2D = otherVector as Vector2D;
if (otherVector2D != null)
return new Vector3D() { X = this.X + otherVector2D.X, Y = this.Y + otherVector2D.Y, Z = this.Z };
Vector3D otherVector3D = otherVector as Vector3D;
if (otherVector3D != null)
return new Vector3D() { X = this.X + otherVector3D.X, Y = this.Y + otherVector3D.Y, Z = this.Z + otherVector3D.Z };
//handle other cases
}
}
EDITx2：
鉴于您的最新评论，也许您应该只维护一个内部数组/矩阵并进行通用矩阵数学运算。您的子类可以针对数组索引公开 X/Y/Z 属性包装器：
public class Vector
{
protected double[] Values;
public int Length { get { return Values.Length; } }
public static Vector operator +(Vector v1, Vector v2)
{
if (v1.Length != v2.Length)
{
throw new VectorTypeException("Vector Dimensions Must Be Equal");
}
else
{
//perform generic matrix addition/operation
double[] newValues = new double[v1.Length];
for (int i = 0; i < v1.Length; i++)
{
newValues[i] = v1.Values[i] + v2.Values[i];
}
//or use some factory/service to give you a Vector2D, Vector3D, or VectorND
return new Vector() { Values = newValues };
}
}
}
public class Vector2D : Vector
{
public double X
{
get { return Values[0]; }
set { Values[0] = value; }
}
public double Y
{
get { return Values[1]; }
set { Values[1] = value; }
}
}
public class Vector3D : Vector
{
public double X
{
get { return Values[0]; }
set { Values[0] = value; }
}
public double Y
{
get { return Values[1]; }
set { Values[1] = value; }
}
public double Z
{
get { return Values[2]; }
set { Values[2] = value; }
}
}
EDITx3：根据您的最新评论，我想您可以在每个子类上实现运算符重载，在静态方法中执行共享逻辑（例如在基本 Vector 类中），然后在某处进行开关/案例检查以提供具体子类：
private static Vector Add(Vector v1, Vector v2)
{
if (v1.Length != v2.Length)
{
throw new VectorTypeException("Vector Dimensions Must Be Equal");
}
else
{
//perform generic matrix addition/operation
double[] newValues = new double[v1.Length];
for (int i = 0; i < v1.Length; i++)
{
newValues[i] = v1.Values[i] + v2.Values[i];
}
//or use some factory/service to give you a Vector2D, Vector3D, or VectorND
switch (newValues.Length)
{
case 1 :
return new Vector1D() { Values = newValues };
case 2 :
return new Vector2D() { Values = newValues };
case 3 :
return new Vector3D() { Values = newValues };
case 4 :
return new Vector4D() { Values = newValues };
//... and so on
default :
throw new DimensionOutOfRangeException("Do not support vectors greater than 10 dimensions");
//or you could just return the generic Vector which doesn't expose X,Y,Z values?
}
}
}
那么你的子类将有：
public class Vector2D
{
public static Vector2D operator +(Vector2D v1, Vector2D v2)
{
return (Vector2D)Add(v1, v2);
}
}
public class Vector3D
{
public static Vector3D operator +(Vector3D v1, Vector3D v2)
{
return (Vector3D)Add(v1, v2);
}
}
有些重复，但我想不出办法让编译器这样做：
Vector3 v1 = new Vector3(2, 2, 2);
Vector3 v2 = new Vector3(1, 1, 1);
var v3 = v1 + v2; //Vector3(3, 3, 3);
Console.WriteLine(v3.X + ", " + v3.Y + ", " + v3.Z);
或其他维度：
Vector2 v1 = new Vector2(2, 2);
Vector2 v2 = new Vector2(1, 1);
var v3 = v1 + v2; //Vector2(3, 3, 3);
Console.WriteLine(v3.X + ", " + v3.Y); // no "Z" property to output!