blocks|key|3293606|text|至于为什么没有，这是一个疏忽。.NET+4中将会有一个Guid.TryParse+(详情请参见BCL+blog+post+)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|3293607|entityMap|0|LINK|mutability|MUTABLE|url|http://blogs.msdn.com/bclteam/archive/2009/10/21/what-s-new-in-the-bcl-in-net-4-beta-2-justin-van-patten.aspx^0|R|D|1B|D|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]]|D|@$9|Q|A|R|1|S]]|E|$]]|$1|F|3|-4|5|6|7|T|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

In terms of why there isn't one, it's an oversight. There will be a <code>Guid.TryParse</code> in .NET 4 (see <a href="http://blogs.msdn.com/bclteam/archive/2009/10/21/what-s-new-in-the-bcl-in-net-4-beta-2-justin-van-patten.aspx" rel="noreferrer">BCL blog post</a> for details).

blocks|key|3293662|text|CLR2.0及更早版本中没有Guid.TryParse。它将从CLR+4.0和Visual+Studio+2010开始可用。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3293663|为什么没有。这类问题通常很难回答正确。这很可能是疏忽或时间限制的问题。如果你在reflector中打开mscorlib，你会看到在Guid上有一个名为TryParse的方法，但它是私有的。在某些情况下，它还会抛出异常，所以它不是一个很好的等价物，比如Int32.TryParse。|offset|length|style|CODE|3293664|entityMap^0|0|1T|4|3H|E|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]|$D|N|E|O|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|P|8|@]|9|@]|A|$]]]|I|$]]

There is no Guid.TryParse in CLR 2.0 and earlier. It will be available starting with CLR 4.0 and Visual Studio 2010.

As to why there wasn't. These types of questions are usually hard to answer correctly. Most likely it was an oversight or a time constraint issue. If you open up mscorlib in reflector you'll see there is actually a method named TryParse on <code>Guid</code> but it's private. It also throws an exception in certain cases so it's not a good equivalent to say <code>Int32.TryParse</code>.

blocks|key|328896|text|使用正则表达式的Guid.TryParse实现。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|328897|entityMap|0|LINK|mutability|MUTABLE|url|http://geekswithblogs.net/colinbo/archive/2006/01/18/66307.aspx^0|8|D|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

<a href="http://geekswithblogs.net/colinbo/archive/2006/01/18/66307.aspx" rel="noreferrer">Guid.TryParse</a> implementation using regular expressions.

blocks|key|324062|text|据我所知，目前.NET框架中没有TryParse功能。您必须求助于RegEx或try-catch选项。RegEx不是我喜欢的，所以我相信其他人会给出答案的。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|324063|异常在性能方面是很昂贵的，所以我选择RegEx选项。|324064|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

There's no TryParse functionality in the .NET Framework to my knowledge at this moment. You'll have to resort to RegEx or the try-catch option. RegEx isn't my cup of tea, so I'm sure someone else will post an answer.

Exceptions are expensive performance wise, so my vote goes to the RegEx option.

blocks|key|324066|text|这应该是可行的：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|324067|@"%5E\{?[0-9a-fA-F]{8}-?[0-9a-fA-F]{4}-?[0-9a-fA-F]{4}-?[0-9a-fA-F]{4}-?[0-9a-fA-F]{12}\}?$"|code-block|syntax|javascript|324068|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This should work:

<pre><code>@"^\{?[0-9a-fA-F]{8}-?[0-9a-fA-F]{4}-?[0-9a-fA-F]{4}-?[0-9a-fA-F]{4}-?[0-9a-fA-F]{12}\}?$"
</code></pre>

blocks|key|3293754|text|您可以编写自己的TryParse作为Guid的扩展方法。然后，当来自微软的“真正的”出现时，你已经可以开始了，并且不需要改变。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3293755|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

You can write your own TryParse as a extension method for Guid. Then when the 'real' one from MS shows up, your already good to go and don't have to change.

blocks|key|324077|text|作为字符串的扩展方法实现的IsGuid+...|type|unstyled|depth|inlineStyleRanges|entityRanges|data|324078|public+static+bool+IsGuid(this+string+stringValue)
{
+++string+guidPattern+=+@"[a-fA-F0-9]{8}(\-[a-fA-F0-9]{4}){3}\-[a-fA-F0-9]{12}";
+++if(string.IsNullOrEmpty(stringValue))
+++++return+false;
+++Regex+guidRegEx+=+new+Regex(guidPattern);
+++return+guidRegEx.IsMatch(stringValue);
}|code-block|syntax|javascript|324079|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

IsGuid implemented as extension method for string...

<pre><code>public static bool IsGuid(this string stringValue)
{
 string guidPattern = @"[a-fA-F0-9]{8}(\-[a-fA-F0-9]{4}){3}\-[a-fA-F0-9]{12}";
 if(string.IsNullOrEmpty(stringValue))
 return false;
 Regex guidRegEx = new Regex(guidPattern);
 return guidRegEx.IsMatch(stringValue);
}
</code></pre>

blocks|key|3080388|text|仅适用于.NET+Framework3.5或更早版本：|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|entityRanges|data|3080389|Guids的这个TryParse实现使用了try-catch来捕获格式错误的Guids。它被实现为扩展方法，并且必须放在静态类中：|CODE|3080390|public+static+bool+TryParseGuid(this+string+s,+out+Guid+guid)
{
++++try+{
++++++++guid+=+new+Guid(s);
++++++++return+true;
++++}+catch+{
++++++++guid+=+Guid.Empty;
++++++++return+false;
++++}
}|code-block|syntax|javascript|3080391|可以使用以下命令调用|3080392|string+s+=+"{CA761232-ED42-11CE-BACD-00AA0057B223}";
Guid+id;
if+(s.TryParseGuid(out+id))+{
++++//+TODO:+use+id
}+else+{
++++//+Sorry+not+a+valid+Guid.
}|3080393|3080394|从C#+7.0+/+Visual+Studio2017开始，您可以使用内联输出变量声明，并通过以下方式调用它：|3080395|string+s+=+"{CA761232-ED42-11CE-BACD-00AA0057B223}";
if+(s.TryParseGuid(out+Guid+id))+{
++++//+TODO:+use+id
}+else+{
++++//+Sorry+not+a+valid+Guid.
}|3080396|3080397|从.NET+Framework4.0开始，System.Guid提供了TryParse和TryPareExact方法，使得上面的代码片段变得过时。|3080398|entityMap^0|4|H|0|8|8|0|0|0|0|0|0|0|0|1|H|L|B|Z|8|18|C|0^^$0|@$1|2|3|4|5|6|7|11|8|@$9|12|A|13|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|14|8|@$9|15|A|16|B|H]]|D|@]|E|$]]|$1|I|3|J|5|K|7|17|8|@]|D|@]|E|$L|M]]|$1|N|3|O|5|6|7|18|8|@]|D|@]|E|$]]|$1|P|3|Q|5|K|7|19|8|@]|D|@]|E|$L|M]]|$1|R|3|-4|5|6|7|1A|8|@]|D|@]|E|$]]|$1|S|3|T|5|6|7|1B|8|@]|D|@]|E|$]]|$1|U|3|V|5|K|7|1C|8|@]|D|@]|E|$L|M]]|$1|W|3|-4|5|6|7|1D|8|@]|D|@]|E|$]]|$1|X|3|Y|5|6|7|1E|8|@$9|1F|A|1G|B|C]|$9|1H|A|1I|B|H]|$9|1J|A|1K|B|H]|$9|1L|A|1M|B|H]]|D|@]|E|$]]|$1|Z|3|-4|5|6|7|1N|8|@]|D|@]|E|$]]]|10|$]]

Only for .NET Framework 3.5 or earlier:
This implementation of a <code>TryParse</code> for Guids uses a try-catch in order to catch missformed Guids. It is implemented as extension method und must be placed in a static class:
<pre><code>public static bool TryParseGuid(this string s, out Guid guid)
{
 try {
 guid = new Guid(s);
 return true;
 } catch {
 guid = Guid.Empty;
 return false;
 }
}
</code></pre>
It can be called with
<pre><code>string s = &quot;{CA761232-ED42-11CE-BACD-00AA0057B223}&quot;;
Guid id;
if (s.TryParseGuid(out id)) {
 // TODO: use id
} else {
 // Sorry not a valid Guid.
}
</code></pre>
<hr />
Starting with C# 7.0 / Visual Studio 2017, you can use an inline out-variable declaration and call it with:
<pre><code>string s = &quot;{CA761232-ED42-11CE-BACD-00AA0057B223}&quot;;
if (s.TryParseGuid(out Guid id)) {
 // TODO: use id
} else {
 // Sorry not a valid Guid.
}
</code></pre>
<hr />
Since .NET Framework 4.0, <code>System.Guid</code> provides <code>TryParse</code> and <code>TryPareExact</code> methods making the code snippets above obsolete.

UPDATE

Guid.TryParse is available in .NET 4.0 

END UPDATE

Obviously there is no public GUID.TryParse() in .NET CLR 2.0.

So, I was looking into regular expressions [aka googling around to find one] and each time I found one there was a heated argument in the comments section about RegEx A doesn't work, use RegEx B. Then someone would write Regex C yadda yadda

So anyway, What I decided to do was this, but I feel bad about it.

<pre><code>public static bool IsGuid (string possibleGuid) {

 try {
 Guid gid = new Guid(possibleGuid);
 return true; 
 } catch (Exception ex) {
 return false;
 }
}
</code></pre>

Obviously I don't really like this since it's been drilled into me since day one to avoid throwing exceptions if you can defensibly code around it.

Does anyone know why there is no public Guid.TryParse() in the .NET Framework?

Does anyone have a real Regular Expression that will work for all GUIDs?

Is there a  GUID.TryParse() in .NET 3.5?

Visual Studio

更新.NET 4.0中提供了Guid.TryParse结束更新显然，在.NET CLR2.0中没有公共的GUID.TryParse()。所以，我在谷歌上搜索正则表达式，每次我找到一个，评论区就会有一场激烈的争论，关于RegEx A不工作，使用RegEx B。然后有人会写Regex C yadda yadda所以不管怎样...

问.NET 3.5中有没有GUID.TryParse()？
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问.NET 3.5中有没有GUID.TryParse()？
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