克隆其基础对象具有许多字段的派生对象 [英] Cloning derived objects whose base objects have many fields

问题描述

假设我有一个名为Vehicle的类，其中包含许多字段。现在我创建了一个新的

类派生自Vehicle的Car。我想创建一种方法将

数据从Vehicle实例复制到Car实例。在Clone（）语句中写一长串

赋值我唯一的选择吗？


我知道我可以使用MemberwiseClone（）编写一个Clone方法，但我的理解是，由MemberwiseClone创建的对象具有相同的

类型。

解决方案

KK，


这不是个好主意。如果您有一个类，Airplane，派生来自Vehicle的
，然后将其传递给要克隆的Car实例，该怎么办？一架

飞机绝对不是一辆车，所以它不应该真的有效。


你想做什么？如果有的话，汽车应该克隆一辆

汽车，或任何来自汽车的东西。


希望这会有所帮助。

-

- Nicholas Paldino [.NET / C＃MVP]

- mv * @ spam .guard.caspershouse.com


" KK" < kkaitan [at] gmail [dot] com>在消息中写道

新闻：％2 **************** @ tk2msftngp13.phx.gbl ...

假设我有一个名为Vehicle的类，有很多字段。现在我创建一个来自Vehicle的新类
类Car。我想制作一种方法将
数据从Vehicle实例复制到Car实例。在Clone（）语句中编写一个长篇系列
分配我唯一的选择吗？

我知道我可以使用MemberwiseClone（）编写一个Clone方法，但我的<理解是由MemberwiseClone创建的对象具有相同的类型。

Nicholas，


对不起，我想我还不清楚。我说我有一个

车辆（基类）的实例。现在我想构建一个新的汽车实例

，其基类字段等于Vehicle实例。我猜它是像汽车的复制构造函数那样的b $ b，除了我没有使用另一辆汽车作为复制的基础，而是一辆车。


希望更有意义。再次感谢！


- KK

Nicholas Paldino [.NET / C＃MVP]" < mv*@spam.guard.caspershouse.com>写在

消息新闻：％2 **************** @ TK2MSFTNGP09.phx.gbl ...

KK，

这不是个好主意。如果您有一个类，Airplane，派生来自Vehicle，然后将其传递给要克隆的Car实例，该怎么办？一架
飞机绝对不是一辆车，所以它不应该真的有用。

你想要做什么？如果有的话，汽车应该克隆
a汽车或任何来自汽车的东西。

希望这会有所帮助。

-
- Nicholas Paldino [。 NET / C＃MVP]
- mv*@spam.guard.caspershouse.com
KK < kkaitan [at] gmail [dot] com>在消息中写道
新闻：％2 **************** @ tk2msftngp13.phx.gbl ...

假设我有一个叫做的课程有很多领域的车辆。现在我创建一个来自Vehicle的新类
类Car。我想制作一种方法将
数据从Vehicle实例复制到Car实例。在Clone（）语句中编写一个长篇系列
分配我唯一的选择吗？

我知道我可以使用MemberwiseClone（）编写一个Clone方法，但我的<理解是，MemberwiseClone创建的对象是
相同的类型。

< blockquote> KK，


确实如此，但你的逻辑是错误的，因为一辆车可以是什么东西

不是汽车，但汽车总是一辆车。

-

- Nicholas Paldino [.NET / C＃MVP]

- mv*@spam.guard.caspershouse.com

" KK" < kkaitan [at] gmail [dot] com>在消息中写道

新闻：ON ************** @ TK2MSFTNGP10.phx.gbl ...

Nicholas，
抱歉，我想我不清楚。我说我有一个
车辆的实例（基类）。现在我想构建一个
Car
的新实例，其基类字段等于Vehicle实例。我想这就像是Car的复制构造器一样，除了我没有使用另一辆车
作为复制的基础，而是车辆。

希望更有意义。再次感谢！

- KK

" Nicholas Paldino [.NET / C＃MVP]" < mv*@spam.guard.caspershouse.com>在
消息新闻中写道
：％2 **************** @ TK2MSFTNGP09.phx.gbl ...

KK，

这不是个好主意。如果您有一个类，Airplane，派生来自Vehicle，然后将其传递给要克隆的Car实例，该怎么办？一架
飞机绝对不是一辆车，所以它不应该真的有用。

你想要做什么？如果有的话，汽车应该克隆

汽车，或任何来自汽车的东西。

希望这会有所帮助。 />
-
- Nicholas Paldino [.NET / C＃MVP]
- mv * @ spam .guard.caspershouse.com

KK < kkaitan [at] gmail [dot] com>在消息中写道
新闻：％2 **************** @ tk2msftngp13.phx.gbl ...

>假设我有一个名为Vehicle的类，有很多字段。现在我做了一个
>新
>派生自Car的车辆。我想制作一个方法来
>复制
>
>从Vehicle实例到Car实例的数据。写得很长
>系列
>
> Clone（）语句中的赋值是我唯一的选择吗？
>
>我知道我可以使用MemberwiseClone（）编写一个Clone方法，但我的
>理解是由MemberwiseClone创建的对象具有相同的>类型。
>
>

Suppose I have a class called Vehicle with many fields. Now I make a new
class derived from Vehicle called Car. I''d like to make a method to copy the
data from a Vehicle instance to a Car instance. Is writing a long series of
assignments in a Clone() statement my only option?

I know that I can write a Clone method using MemberwiseClone(), but my
understanding is that the object created by MemberwiseClone is of the same
type.

解决方案

K.K.,

This isn''t a good idea. What if you have a class, Airplane, derived
from Vehicle, and then pass that to a Car instance to be cloned? An
Airplane definitely isn''t a car, so it shouldn''t really work.

What is it that you are trying to do? If anything, a Car should clone a
Car, or anything deriving from Car.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"K.K." <kkaitan [at] gmail [dot] com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...

Suppose I have a class called Vehicle with many fields. Now I make a new
class derived from Vehicle called Car. I''d like to make a method to copy
the
data from a Vehicle instance to a Car instance. Is writing a long series
of
assignments in a Clone() statement my only option?

I know that I can write a Clone method using MemberwiseClone(), but my
understanding is that the object created by MemberwiseClone is of the same
type.

Nicholas,

Sorry, I guess I wasn''t clear. I''m saying that I have an instance of a
Vehicle (the base class). Now I''d like to construct a new instance of a Car
whose base-class fields are equal to the Vehicle instance. I guess it''s sort
of like a copy constructor for Car, except that I''m not using another Car as
the basis for the copying, but rather a Vehicle.

Hope that makes a little more sense. Thanks again!

- KK
"Nicholas Paldino [.NET/C# MVP]" <mv*@spam.guard.caspershouse.com> wrote in
message news:%2****************@TK2MSFTNGP09.phx.gbl...

K.K.,

This isn''t a good idea. What if you have a class, Airplane, derived
from Vehicle, and then pass that to a Car instance to be cloned? An
Airplane definitely isn''t a car, so it shouldn''t really work.

What is it that you are trying to do? If anything, a Car should clone a Car, or anything deriving from Car.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"K.K." <kkaitan [at] gmail [dot] com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...

Suppose I have a class called Vehicle with many fields. Now I make a new
class derived from Vehicle called Car. I''d like to make a method to copy
the
data from a Vehicle instance to a Car instance. Is writing a long series
of
assignments in a Clone() statement my only option?

I know that I can write a Clone method using MemberwiseClone(), but my
understanding is that the object created by MemberwiseClone is of the same type.

KK,

It does, but your logic is wrong, because a Vehicle can be something
that is not a Car, but a Car is always a Vehicle.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"K.K." <kkaitan [at] gmail [dot] com> wrote in message
news:ON**************@TK2MSFTNGP10.phx.gbl...

Nicholas,

Sorry, I guess I wasn''t clear. I''m saying that I have an instance of a
Vehicle (the base class). Now I''d like to construct a new instance of a
Car
whose base-class fields are equal to the Vehicle instance. I guess it''s
sort
of like a copy constructor for Car, except that I''m not using another Car
as
the basis for the copying, but rather a Vehicle.

Hope that makes a little more sense. Thanks again!

- KK
"Nicholas Paldino [.NET/C# MVP]" <mv*@spam.guard.caspershouse.com> wrote
in
message news:%2****************@TK2MSFTNGP09.phx.gbl...

K.K.,

This isn''t a good idea. What if you have a class, Airplane, derived
from Vehicle, and then pass that to a Car instance to be cloned? An
Airplane definitely isn''t a car, so it shouldn''t really work.

What is it that you are trying to do? If anything, a Car should
clone

a

Car, or anything deriving from Car.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"K.K." <kkaitan [at] gmail [dot] com> wrote in message
news:%2****************@tk2msftngp13.phx.gbl...

> Suppose I have a class called Vehicle with many fields. Now I make a
> new
> class derived from Vehicle called Car. I''d like to make a method to
> copy
> the
> data from a Vehicle instance to a Car instance. Is writing a long
> series
> of
> assignments in a Clone() statement my only option?
>
> I know that I can write a Clone method using MemberwiseClone(), but my
> understanding is that the object created by MemberwiseClone is of the same > type.
>
>

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