A potentially dangerous Request.Path value was detected from the client 异常

我们在ASP.net 4.0 中使用URL导向后， 我们在访问类似如下的地址一个面试题!********/，就会报错误： 

A potentially dangerous Request.Path value was detected from the client

at System.Web.HttpRequest.ValidateInputIfRequiredByConfig()  

at System.Web.HttpApplication.ValidateRequestExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()  

at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

这是因为上述地址中有*这个特殊字符存在。

如果你想不让ASP.net 替你拦截这些特殊字符，你需要设置如下Web.config的节：

<?xml version="1.0"?>
<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">
<system.web>
<httpRuntime requestPathInvalidCharacters="" />
</system.web>
</configuration>

注意其中的requestPathInvalidCharacters

即，不设置这个属性，默认就是如下设置：

<?xml version="1.0"?>
<configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">
<system.web>
<httpRuntime requestPathInvalidCharacters="<,>,*,%,:,&,\" />
</system.web>
</configuration>

如果你想这些字符全部不受限制，就应该设置 requestPathInvalidCharacters="" , 如果是部分字符受限制，部分字符不受限制，就需要在 requestPathInvalidCharacters

参考资料：

Experiments in Wackiness: Allowing percents, angle-brackets, and other naughty things in the ASP.NET/IIS Request URL
http://www.budoou.com/article/981320/