当“ToString”时不等于“ToString” [英] When "ToString" does not equal "ToString"
问题描述
我有一个非常奇怪的问题，在我的代码的某些部分我比较两个
字符串（通过对象），而我*知道*它们相等每个
其他，并且在观察窗口他们彼此相等，然后
比较返回false。
详情请见此处：
http ：//www.ayende.com/Blog/PermaLink...c876a6acb.aspx
I''ve a really strange problem, in some part of my code I compare two
strings (through object), and while I *know* that they equal each
other, and in the watch window they do equal each other, then the
comparision return false.
See here for details:
http://www.ayende.com/Blog/PermaLink...c876a6acb.aspx
推荐答案
Ayende Rahien写道：
Ayende Rahien wrote:
我有一个非常奇怪的问题，在我的代码的某些部分我比较两个
字符串（通过对象），而我*知道*它们相等每个
其他，并且在观察窗口他们相互平等，然后
比较返回false。
详情请见这里：
http://www.ayende.com/Blog/PermaLink...34f-bfe0-39ac8
76a6acb.aspx
I''ve a really strange problem, in some part of my code I compare two
strings (through object), and while I *know* that they equal each
other, and in the watch window they do equal each other, then the
comparision return false.
See here for details:
http://www.ayende.com/Blog/PermaLink...34f-bfe0-39ac8
76a6acb.aspx
问题在于字符串既不是引用类型也不是值类型！
它们以特殊方式处理...
在您的情况下，您正在比较可能不同的对象引用！
使用string.Compare（a，b）或a.CompareTo（b）或a.Equals（b）
-
问候
Jochen
关于Win32和.NET的博客
http://blog.kalmbachnet.de/
失败的代码是
if（o == test）？
well o和test都输入为对象，因此您正在使用System.Object ==运算符，交给System.Object.ReferenceEquals。换句话说，如果o和test是相同的物理对象，则onyl会成功比较
问候
Richard Blewett - DevelopMentor http://staff.develop.com/richardb/weblog
nntp：//news.microsoft.com/microsoft.public.dotnet.languages.csharp/< 29 ***************** ********@posting.google.com>
我有一个非常奇怪的问题，在我的代码的某些部分我比较两个
字符串（通过对象），虽然我知道*他们等于每个
其他，并且在观察窗口他们彼此相等，然后
比较返回false。
详见此处：
http://www.ayende.com/Blog/PermaLink...c876a6acb.aspx
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[microsoft.public.dotnet.languages.csharp]
The code that is failing is the
if( o == test) ?
well o and test are both typed as object so you are using the System.Object == operator which hands off to System.Object.ReferenceEquals. In other words, the comparison will onyl succeed if o and test are teh same physical object
Regards
Richard Blewett - DevelopMentor
http://staff.develop.com/richardb/weblog
nntp://news.microsoft.com/microsoft.public.dotnet.languages.csharp/<29*************************@posting.google.com>
I''ve a really strange problem, in some part of my code I compare two
strings (through object), and while I *know* that they equal each
other, and in the watch window they do equal each other, then the
comparision return false.
See here for details:
http://www.ayende.com/Blog/PermaLink...c876a6acb.aspx
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Checked by AVG anti-virus system (http://www.grisoft.com).
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[microsoft.public.dotnet.languages.csharp]
嗯，字符串是引用类型。它们是不可变的，导致某些值像行为但它们肯定是引用类型（即在托管堆上分配，称为32位引用，并且是垃圾收集。
问候
Richard Blewett - DevelopMentor
http ：//staff.develop.com/richardb/weblog
nntp：//news.microsoft.com/microsoft.public.dotnet.languages.csharp/< Xn**********************************@207.46.248.1 6>
Ayende Rahien写道：
Umm, strings are reference types. They are immutable which results in some value like behavior but they are definitely reference types (i.e. allocated on the managed heap, referred to vai a 32 bit reference and are garbage collected.
Regards
Richard Blewett - DevelopMentor
http://staff.develop.com/richardb/weblog
nntp://news.microsoft.com/microsoft.public.dotnet.languages.csharp/<Xn**********************************@207.46.248.1 6>
Ayende Rahien wrote:
我有一个非常奇怪的问题，在我的代码的某些部分我比较两个
字符串（通过对象），而我*知道*他们相等于其他人，并且在观察窗口他们彼此相等，然后
比较返回假。
详情请见此处：
http://www.ayende.com/Blog/PermaLink...34f-bfe0-39ac8
76a6acb.aspx
I''ve a really strange problem, in some part of my code I compare two
strings (through object), and while I *know* that they equal each
other, and in the watch window they do equal each other, then the
comparision return false.
See here for details:
http://www.ayende.com/Blog/PermaLink...34f-bfe0-39ac8
76a6acb.aspx
问题在于字符串既不是引用类型也不是值类型！
它们以特殊方式处理...
在您的情况下，您正在比较可能不同的对象引用！
使用string.Compare（a，b）或a.CompareTo（b）或a.Equals（b）
-
问候
Jochen
关于Win32和.NET的博客
http://blog.kalmbachnet.de/
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[microsoft.public.dotnet.languages.csharp]
The problem is that "strings" are neither reference types nor value types!
They are handled in a special way...
In your case you are comparing object references which might be different!
Either use string.Compare(a, b) or a.CompareTo(b) or a.Equals(b)
--
Greetings
Jochen
My blog about Win32 and .NET
http://blog.kalmbachnet.de/
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[microsoft.public.dotnet.languages.csharp]
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