string VBScript 的 + 和 & 运算符有什么区别？
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What is the difference between VBScript's + and & operator?
提问by Jeremy Cron
On every site that talks about VBScript, the '&' operator is listed as the string concatenation operator. However, in some code that I have recently inherited, I see the '+' operator being used and I am not seeing any errors as a result of this. Is this an accepted alternative?
在每个讨论 VBScript 的站点上，' &' 运算符都被列为字符串连接运算符。但是，在我最近继承的一些代码中，我看到使用了 ' +' 运算符，并且我没有看到任何由此产生的错误。这是可接受的替代方案吗？
回答by Helen
The &operator does string concatenation, that is, forces operands to be converted to strings (like calling CStron them first). +, in its turn, forces addition if one of the expressions is numeric. For example:
该&运营商做字符串连接，那就是势力的操作数转换为字符串（如调用CStr它们在前）。+，反过来，如果表达式之一是数字，则强制加法。例如：
1 & 2
gives you 12, whereas
给你12，而
1 + 2
"1" + 2
1 + "2"
give you 3.
给你3。
So, it is recommended to use &for string concatenation since it eliminates ambiguity.
因此，建议&用于字符串连接，因为它消除了歧义。
回答by Robert Harvey
The + operator is overloaded, whereas the & operator is not. The & operator only does string concatenation. In some circles the & operator is used as a best practice because it is unambiguous, and therefore cannot have any unintended effects as a result of the overloading.
+ 运算符被重载，而 & 运算符不是。& 运算符只进行字符串连接。在某些圈子中，& 运算符被用作最佳实践，因为它是明确的，因此不会因重载而产生任何意外影响。
回答by EFraim
+operator might backfire when strings can be interpreted as numbers. If you don't want nasty surprises use & to concatenate strings.
+当字符串可以解释为数字时，运算符可能会适得其反。如果您不想要令人讨厌的惊喜，请使用 & 连接字符串。
回答by Neal Davis
In some cases the + will throw an exception; for example the following:
在某些情况下，+ 会抛出异常；例如以下内容：
Sub SimpleObject_FloatPropertyChanging(fvalue, cancel)
'fvalue is a floating point number
MsgBox "Received Event: " + fvalue
End Sub
You will get an exception when the COM object source fires the event - you must do either of the following:
当 COM 对象源触发事件时，您将收到异常 - 您必须执行以下任一操作：
MsgBox "Received Event: " & fvalue
or
或者
MsgBox "Received Event: " + CStr(fvalue)
It may be best in either case to use CStr(value); but using & per above comments for string concatenation is almost always best practice.
在这两种情况下最好使用CStr(value); 但是使用 & per 上面的注释进行字符串连接几乎总是最佳实践。
