我想使用 VirtualPathUtility.ToAbsolute $解决应用程序相对路径，如〜/ MyPage.aspx ，应用绝对路径，如 /MySite/MyApp/MyPage.aspx 。然而，一些路径，我收到一封 HttpException 说我的路径是不是有效的虚拟路径。例如：

I'm trying to use VirtualPathUtility.ToAbsolute to resolve app-relative paths, such as ~/MyPage.aspx, to application-absolute paths, such as /MySite/MyApp/MyPage.aspx. However, with some paths, I receive an HttpException saying that my path is "not a valid virtual path". Examples:

// This works:
var abs1 = VirtualPathUtility.ToAbsolute("~/MyPage.aspx#anchor");

// This errors:
var abs2 = VirtualPathUtility.ToAbsolute("~/MyPage.aspx?key=value");

这是怎么回事？

What's going on?

推荐答案

由于您使用的是.NET 3.5，您使用的是 2.0 的System.Web 组件，它有一个？被认为是由该方法非法路径字符。这是中提到的特定版本的MSDN页面

Because you're using .NET 3.5, you're using the 2.0 System.Web assembly, which has the defect that ? is considered an illegal path character by this method. This is mentioned in the community comments on the version-specific MSDN page.

通过拆卸，可以看出，呼叫终止于（内部） VirtualPath.Create ，其中有：

By disassembling, it can be seen that the call ends up in the (internal) VirtualPath.Create, which has:

  else if (VirtualPath.ContainsIllegalVirtualPathChars(virtualPath))
  {
    throw new HttpException(System.Web.SR.GetString("Invalid_vpath", new object[1]
    {
      (object) virtualPath
    }));
  }

该引用

private static char[] s_illegalVirtualPathChars = new char[4]
{
  ':',
  '?',
  '*',
  char.MinValue
};

有些可以合理地认为是坏字符的路径，但？真不该这么拒绝了。

Some of these can reasonably be regarded as bad characters for a path, but ? shouldn't really be so rejected.

的 4.0 的System.Web 显示反汇编 VirtualPath.Create 已被重写，更加挑剔。

Disassembly of the 4.0 System.Web shows that VirtualPath.Create has been rewritten to be more discerning.

This一个现在已不存在blogs.msdn帖子的web.archive截图显示的最早提到这个问题。在MS员工响应：

This web.archive capture of a now-defunct blogs.msdn post shows one of the earliest mentions of this problem. The MS employee responds:

星期日，2006年2月26日下午11点49由DmitryR异常对〜/路径？QS   是，我需要修复bug ......

Sunday, February 26, 2006 11:49 PM by DmitryR Exception on ~/path?qs is a bug that I'll need to fix...

最简单的解决方法是保存/恢复的查询字符串    ResolveAp prelativeLinkToUrl 围绕呼叫    VirtualPathUtility.ToAbsolute 。

The easiest fix is to save/restore query string in ResolveAppRelativeLinkToUrl around the call to VirtualPathUtility.ToAbsolute.

一个解决办法是使用完全合格UTLS，而不是〜/...".

A workaround is to use fully qualified UTLs instead of "~/...".

谢谢

梅德

其中， ResolveAp prelativeLinkToUrl 指的是记者的code的方法名。

where ResolveAppRelativeLinkToUrl refers to the reporter's code's method name.

另一个解决办法是更换？的调用之前一个安全令牌 VirtualPathUtility.ToAbsolute 和反向更换算账：

Another workaround would be to replace ? with a safe token before the call to VirtualPathUtility.ToAbsolute, and reverse the replacement afterwards:

public static string SafeToAbsolute(string path)
{
    var madeSafe = path.Replace("?", "UNLIKELY_TOKEN");
    var absolute = VirtualPathUtility.ToAbsolute(madeSafe);
    var restored = absolute.Replace("UNLIKELY_TOKEN", "?");
    return restored;
}

选择一个合适不可能令牌应用程序。

choosing a suitably unlikely token for your application.