System.Web.HttpException: '' is not a vaid path

Question

I have the following helper method:

    public static String ResolveUrl(String url)
    {
        url = url.Trim();
        if (!(url[0] == '~')) return url;
        try
        {
            if (VirtualPathUtility.IsAppRelative(url)) return VirtualPathUtility.ToAbsolute(url);
            return url;
        }
        catch (HttpException)
        {
            return url;
        }
    }

The problem is that it raises an exception if the provided URL contains a querystring, eg. ~/showcase/View.aspx?id=10783.

Stack trace:

System.Web.HttpException was caught
  Message='~/showcase/View.aspx?id=10783' is not a valid virtual path.
  Source=System.Web
    ErrorCode=-2147467259
    StackTrace:
         at System.Web.VirtualPath.Create(String virtualPath, VirtualPathOptions options)
         at System.Web.VirtualPathUtility.IsAppRelative(String virtualPath)
         at Ctf.Common.ResolveUrl(String url) in [redacted]Common.cs:line 359
    InnerException:

What's the problem here? Does VirtualPathUtility just not support querystring URLs?

Edit: I should add that the helper is perfectly fine with other app-relative URLs as long as there isn't a querystring on them.

Edit2: I've made a hack workaround by removing the querystring from the URL before calling the VirtualPathUtility methods, then gluing it back on at the end. I'd rather avoid this if possible.

does it perhaps expect an absolute url, and is rejecting yours since it doesn't have `http://example.com/~....`? — Marc B, Aug 20 '14 at 20:20
The whole point of `VirtualPathUtility.IsAppRelative` is to detect whether the URL is an app-relative path, ie. begins with `~/`. — mm201, Aug 20 '14 at 20:24

score 1 · Accepted Answer · edited May 23 '17 at 11:49

1

If you are using .NET 3.5 and below, then you are right, VirtualPathUtility will not accept a query string as a valid part of a virtual path for those methods. You'll have to trim off the query string and re-append it on your absolute URL. Check out this excellent question / answer Why do I get an HttpException from VirtualPathUtility ToAbsolute with some paths?.

edited May 23 '17 at 11:49

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answered Aug 20 '14 at 20:32

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System.Web.HttpException: '' is not a vaid path

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