[英]IsNumeric() not working with Request.QueryString
I'm having problems trying to get IsNumeric to work properly with Request.QueryString. 我在尝试让IsNumeric与Request.QueryString一起正常工作时遇到了问题。
The server is Windows 2008 R2 / IIS7.5 服务器是Windows 2008 R2 / IIS7.5
My code could not be any simpler: 我的代码不能再简单了:
<%@ LANGUAGE=VBScript %>
<% Response.Write "IsNumeric: " & IsNumeric(Request.QueryString("")) %>
My URL: http://localhost.com/default2.asp?44hjh 我的网址: http : //localhost.com/default2.asp?44hjh
The output: IsNumeric: True 输出:IsNumeric:True
If I change my code to this, then I get the desired outcome: 如果我将我的代码更改为此,那么我会得到所需的结果:
<%@ LANGUAGE=VBScript %>
<% Response.Write "IsNumeric: " & IsNumeric(Request.QueryString("test")) %>
My URL: http://localhost.com/default2.asp?test=44hjh 我的网址: http : //localhost.com/default2.asp?test = 44hjh
The output: IsNumeric: False 输出:IsNumeric:False
Why does IsNumeric not work when I don't specify a specific querystring element? 当我没有指定特定的查询字符串元素时,为什么IsNumeric不起作用? And more importantly, how can I fix it? 更重要的是,我该如何解决?
Request.QueryString("")
doesn't exist and thus returns NULL
-- there isn't a parameter that is a blank. Request.QueryString("")
不存在,因此返回NULL
- 没有一个空白的参数。 IsNumeric
of a NULL
value will return True. NULL
值的IsNumeric
将返回True。
Instead of using Request.QueryString("")
, you can either supply the parameter as you did in your 2nd example, or just use Request.QueryString
by itself assuming no other parameters are being passed to your page: 您可以像在第二个示例中那样提供参数,而不是使用Request.QueryString("")
,或者只使用Request.QueryString
,假设没有其他参数传递到您的页面:
<% Response.Write "IsNumeric: " & IsNumeric(Request.QueryString) %>
That's because isnumeric
of a null value returns an integer type. 那是因为null值的isnumeric
返回一个整数类型。 That's why you get a TRUE in the first case. 这就是为什么你在第一种情况下获得TRUE的原因。 Whereas you are checking for a string type using the isnumeric
in the second case. 而您在第二种情况下使用isnumeric
检查字符串类型。
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