在派生类的构造函数中设置只读。 [英] Set readonly in constructor of a derived class.
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问题描述
我知道不允许以下内容，但不应该这样吗？ sharedObject是衍生的
的一部分，应该能够在构造函数中设置 - 不是吗？ tia
公共抽象类Base1
{
protected readonly object sharedObject;
}
公共类派生：Base1
{
public Derived（）
{
sharedObject = new object（）;
}
}
-
William Stacey，MVP
I know the following is not allowed, but shouldn''t it be? sharedObject is
part of Derived and should be able to be set in the constructor - no? tia
public abstract class Base1
{
protected readonly object sharedObject;
}
public class Derived : Base1
{
public Derived()
{
sharedObject = new object();
}
}
--
William Stacey, MVP
推荐答案
Hi William，
readonly关键字是一个可以在字段上使用的修饰符。当字段
声明包含只读修饰符时，声明引入的字段
的赋值只能作为声明的一部分出现或
在同一个类的构造函数中。
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
这是详细信息的链接。
http://msdn.microsoft.com/library/de...us/csref/html/
vclrfreadonlypg.asp
问候，
Peter Huang
Microsoft在线合作伙伴支持
安全！ www.microsoft.com/security
此帖子是提供按原样没有保证，也没有赋予任何权利。
--------------------
Hi William,
The readonly keyword is a modifier that you can use on fields. When a field
declaration includes a readonly modifier, assignments to the fields
introduced by the declaration can only occur as part of the declaration or
in a constructor in the same class.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Here is the link for detail information.
http://msdn.microsoft.com/library/de...us/csref/html/
vclrfreadonlypg.asp
Regards,
Peter Huang
Microsoft Online Partner Support
Get Secure! www.microsoft.com/security
This posting is provided "as is" with no warranties and confers no rights.
--------------------
来自： 威廉斯泰西 < st ***** @ mvps.org>
主题：在派生类的构造函数中设置只读。
日期：2003年10月7日星期二00:10:08 -0400
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我知道不允许以下内容，但不应该这样吗？ sharedObject是Derived的一部分，应该能够在构造函数中设置 - 不是吗？ tia
公共抽象类Base1
{
受保护的readonly对象sharedObject;
}
public class Derived：Base1
{
公共派生（）
{
sharedObject = new object（）;
}
}
-
William Stacey，MVP
From: "William Stacey" <st*****@mvps.org>
Subject: Set readonly in constructor of a derived class.
Date: Tue, 7 Oct 2003 00:10:08 -0400
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I know the following is not allowed, but shouldn''t it be? sharedObject is
part of Derived and should be able to be set in the constructor - no? tia
public abstract class Base1
{
protected readonly object sharedObject;
}
public class Derived : Base1
{
public Derived()
{
sharedObject = new object();
}
}
--
William Stacey, MVP
William Stacey< st ***** @ mvps。有机>写道：
William Stacey <st*****@mvps.org> wrote:
我知道以下是不允许的，但不应该吗？ sharedObject是Derived的一部分，应该能够在构造函数中设置 - 不是吗？
I know the following is not allowed, but shouldn''t it be? sharedObject is
part of Derived and should be able to be set in the constructor - no?
< snip>
除了Peter给出的答案之外，我还建议将任何
字段非私有至少*通常是一个坏主意。对于一次性课程来说，这不是很糟糕
，或者可能是嵌套课程只能看到封闭课程的嵌套课程，但是我会避免使用它们其他。
-
Jon Skeet - < sk *** @ pobox.com>
http://www.pobox.com/~skeet
如果回复群组，请不要给我发邮件
<snip>
As well as the answer given by Peter, I''d also suggest that making any
fields non-private is at least *usually* a bad idea. It''s not so bad
for throwaway classes, or perhaps nested classes that are only visible
to the enclosing class, but I''d steer away from using them elsewhere.
--
Jon Skeet - <sk***@pobox.com>
http://www.pobox.com/~skeet
If replying to the group, please do not mail me too
谢谢彼得。我理解readonly的正常用法。不过我要问b $ b问一个不同的问题。由于Derived继承了sharedObject，而Base1
是抽象的，因此不是sharedObject。 Derived类的成员？如果是这样的话，
为什么Derived中的*构造函数不能在其构造函数中设置值？
-
William Stacey，MVP
" Peter Huang [MSFT]" <，V - ****** @ online.microsoft.com>在消息中写道
news：bt ************** @ cpmsftngxa06.phx.gbl ...
Thanks Peter. I understand the normal usage of readonly. However I am
asking a different question. As Derived inherits "sharedObject", and Base1
is abstract, isn''t "sharedObject" a member of the Derived class? And if so,
why can''t the *constructor in Derived set the value in its'' constructor?
--
William Stacey, MVP
"Peter Huang [MSFT]" <v-******@online.microsoft.com> wrote in message
news:bt**************@cpmsftngxa06.phx.gbl...
Hi William，
readonly关键字是一个可以在字段上使用的修饰符。当
字段声明包含一个只读修饰符时，声明引入的字段的赋值只能作为声明的一部分出现，或者在同一类的构造函数中出现。
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
这是详细信息的链接。
http://msdn.microsoft.com/ library / de ... us / csref / html / vclrfreadonlypg.asp
问候，
Peter Huang
微软在线合作伙伴支持
获得安全保障！ www.microsoft.com/security
此帖子提供为as as是"没有保证，也没有赋予任何权利。
--------------------
Hi William,
The readonly keyword is a modifier that you can use on fields. When a field declaration includes a readonly modifier, assignments to the fields
introduced by the declaration can only occur as part of the declaration or
in a constructor in the same class.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Here is the link for detail information.
http://msdn.microsoft.com/library/de...us/csref/html/ vclrfreadonlypg.asp
Regards,
Peter Huang
Microsoft Online Partner Support
Get Secure! www.microsoft.com/security
This posting is provided "as is" with no warranties and confers no rights.
--------------------
来自：William Stacey ; < st ***** @ mvps.org>
主题：在派生类的构造函数中设置只读。
日期：2003年10月7日星期二00:10:08 -0400
行数：23
X-Priority：3
X-MSMail-Priority：正常
X-Newsreader：Microsoft Outlook Express 6.00.3790.0
X-MimeOLE：由Microsoft MimeOLE V6制作.00.3790.0
消息ID：<或************** @ TK2MSFTNGP09.phx.gbl>
新闻组：microsoft.public.dotnet.languages。 csharp
NNTP-Posting-Host：66.188.59.114.bay.mi.chartermi.net 66.188.59.114
路径：
From: "William Stacey" <st*****@mvps.org>
Subject: Set readonly in constructor of a derived class.
Date: Tue, 7 Oct 2003 00:10:08 -0400
Lines: 23
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.3790.0
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.3790.0
Message-ID: <Or**************@TK2MSFTNGP09.phx.gbl>
Newsgroups: microsoft.public.dotnet.languages.csharp
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Path:
cpmsftngxa06.phx.gbl！TK2MSFTNGXA06 .phx.gbl！TK2MSFT NGXA05.phx.gbl！TK2MSFTNGP0 8.phx.gbl！TK2MSFTNGP09.phx.gbl
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Xref：cpmsftngxa06.phx.gbl
microsoft.public.dotnet.languages .csharp：189441X-Tomcat-NG：microsoft.public.dotnet.languages.csharp
我知道不允许以下内容，但不应该这样吗？ sharedObject
是Derived的部分，应该能够在构造函数中设置 - 不是吗？
tia
公共抽象类Base1
{
受保护的readonly对象sharedObject;
}
公共类派生：Base1
{
公共派生（）
{
sharedObject = new object（）;
}
}
-
William Stacey，MVP
Xref: cpmsftngxa06.phx.gbl microsoft.public.dotnet.languages.csharp:189441X-Tomcat-NG: microsoft.public.dotnet.languages.csharp
I know the following is not allowed, but shouldn''t it be? sharedObject ispart of Derived and should be able to be set in the constructor - no? tia
public abstract class Base1
{
protected readonly object sharedObject;
}
public class Derived : Base1
{
public Derived()
{
sharedObject = new object();
}
}
--
William Stacey, MVP
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