问题描述
我们最近升级的.NET 3.5的所有项目，以.NET 4我所遇到的一个比较奇怪的问题，相对于 string.IndexOf（）。
We have recently upgraded all our projects from .NET 3.5 to .NET 4. I have come across a rather strange issue with respect to string.IndexOf().
我的code显然做了略有不同，但在调查该问题的过程中，我发现，调用的IndexOf（）上的绳子与自身返回1而不是0。换句话说：
My code obviously does something slightly different, but in the process of investigating the issue, I found that calling IndexOf() on a string with itself returned 1 instead of 0.In other words:
string text = "\xAD\x2D"; // problem happens with "-dely N.China", too;
int index = text.IndexOf(text); // see update note below.
给我的1，0几件事情要注意这个问题的指标，而不是：
Gave me an index of 1, instead of 0. A couple of things to note about this problem:
-
该问题似乎与这些连字符（第一个字符是统一code软连字符，第二个是一个普通的连字符）。
The problems seems related to these hyphens (the first character is the Unicode soft hyphen, the second is a regular hyphen).
我有双重检查，这种情况不会发生在.NET 3.5，但确实在.NET 4中。
I have double checked, this does not happen in .NET 3.5 but does in .NET 4.
更改的IndexOf（）做一个序对比修复的问题，因此对于一些原因，第一个字符被忽略，默认的IndexOf 。
Changing the IndexOf() to do an ordinal compare fixes the issue, so for some reason that first character is ignored with the default IndexOf.
有谁知道为什么会这样？
Does anyone know why this happens?
修改
对不起球员，做了一个有点东西了在原来的职位，并得到了隐藏的冲刺中就有两次。我已经更新了字符串，这应该回报指数为1，而不是2，只要您将其粘贴在正确的编辑器。
Sorry guys, made a bit of a stuff up on the original post and got the hidden dash in there twice. I have updated the string, this should return index of 1 instead of 2, as long as you paste it in the correct editor.
更新：
改变了原来的问题串一个，每一个字符是清晰可见（使用转义）。这简化了问题了一下。
Changed the original problem string to one where every actual character is clearly visible (using escaping). This simplifies the question a bit.
推荐答案
您字符串的两个字符存在：一个的（统一code code点173）和的（统一code code点45）。
Your string exists of two characters: a soft hyphen (Unicode code point 173) and a hyphen (Unicode code point 45).
维基的：根据统一code标准，则不会显示软连字符，如果该行不在该点断裂。
在使用\ XAD \ X2D.IndexOf（\ XAD \ X2D）在.NET 4中，它似乎忽略了，你要寻找的软连字符，返回1（的 \ X2D指数）的起始索引。在.NET 3.5中，则返回0。
When using "\xAD\x2D".IndexOf("\xAD\x2D") in .NET 4, it seems to ignore that you're looking for the soft hyphen, returning a starting index of 1 (the index of \x2D). In .NET 3.5, this returns 0.
更多乐趣，如果你运行此code（所以当的只有的寻找软连字符）：
More fun, if you run this code (so when only looking for the soft hyphen):
string text = "\xAD\x2D";
string shy = "\xAD";
int i1 = text.IndexOf(shy);
然后 I1 变为0，而不管使用的.NET版本。 text.IndexOf（文字）的结果; 确实有所不同，这一眼看起来像我的错误。
then i1 becomes 0, regardless of the .NET version used. The result of text.IndexOf(text); varies indeed, which at a glance looks like a bug to me.
据我可以追溯通过框架，旧的.NET版本使用的InternalCall以 IndexOfString（）（我想不出哪个API调用云），而.NET 4的以 InternalFindNLSStringEx（）制成，后者又调用<$c$c>FindNLSStringEx().
As far as I can track back through the framework, older .NET versions use an InternalCall to IndexOfString() (I can't figure out to which API call that goes), while from .NET 4 a QCall to InternalFindNLSStringEx() is made, which in turn calls FindNLSStringEx().
这个问题（我实在想不通，如果这是预期的行为）时调用 FindNLSStringEx 确实发生：
The issue (I really can't figure out if this is intended behaviour) indeed occurs when calling FindNLSStringEx:
LPCWSTR lpStringSource = L"\xAD\x2D";
LPCWSTR lpStringValue = L"\xAD";
int length;
int i = FindNLSStringEx(
LOCALE_NAME_SYSTEM_DEFAULT,
FIND_FROMSTART,
lpStringSource,
-1,
lpStringValue,
-1,
&length,
NULL,
NULL,
1);
Console::WriteLine(i);
i = FindNLSStringEx(
LOCALE_NAME_SYSTEM_DEFAULT,
FIND_FROMSTART,
lpStringSource,
-1,
lpStringSource,
-1,
&length,
NULL,
NULL,
1);
Console::WriteLine(i);
Console::ReadLine();
打印0，然后1。注意，长度，之后的第二个第一个呼叫，1之后的输出参数指示找到字符串的长度，为0;软连字符被计数为具有的长度为0。
Prints 0 and then 1. Note that length, an out parameter indicating the length of the found string, is 0 after the first call and 1 after the second; the soft hyphen is counted as having a length of 0.
解决方法是使用 text.IndexOf（文字，StringComparison.OrdinalIgnoreCase）; ，因为你已经注意到。这使得QCall到 InternalCompareStringOrdinalIgnoreCase（），接着调用<$c$c>FindStringOrdinal(),这两种情况下返回0
The workaround is to use text.IndexOf(text, StringComparison.OrdinalIgnoreCase);, as you've noted. This makes a QCall to InternalCompareStringOrdinalIgnoreCase() which in turn calls FindStringOrdinal(), which returns 0 for both cases.
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