Why are my users not able to verify their email address? - asp.net

Question

I'm using a uniqueidentifier to validate the email address of a user in my ASP.NET application. When I try to validate any email address using the uniqueidentifier, I can do so without problem. 80% of my users, however, cannot do so. I cannot figure out why this is happening! I've had users email me directly, forwarding their activation email and I can activate their account without issue.
Here's an example of the validation link that's in the email.
mysite.org/petition.aspx?uid=0fcc9582-386c-4738-943d-36e09c8df4bd
Here's the exception that's occurring:
problem loading petition screen: Guid should contain 32 digits with 4 dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx).:
at System.Guid.GuidResult.SetFailure(ParseFailureKind failure, String failureMessageID, Object failureMessageFormatArgument, String failureArgumentName, Exception innerException)
at System.Guid.TryParseGuidWithDashes(String guidString, GuidResult& result)
at System.Guid.TryParseGuid(String g, GuidStyles flags, GuidResult& result)
at System.Guid..ctor(String g)
at MAP.Umbraco.UserControls.SignPetitionUserControl.get_PetitionGuid()
at MAP.Umbraco.UserControls.SignPetitionUserControl.OnLoad(EventArgs e)
UPDATE: Here's the get method for my PetitionGuid property.
private Guid? PetitionGuid
{
get
{
if (Page.Request.QueryString["uid"] == null)
return null;
else
return new Guid( Page.Request.QueryString["uid"].ToString());
}
}
Is there anything obvious that I'm missing here?
Feel free to ask any questions that you might need to ask.

Answer 1

You're missing a character.
0fcc9582-386c-4738-943d-36e09c8df4b <---
12345678 1234 1234 1234 123456789012
Update
Based on your update above, your implementation for petition guid is not coded very defensively.
private Guid? PetitionGuid
{
get
{
if (Page.Request.QueryString["uid"] == null)
return null;
else
return new Guid( Page.Request.QueryString["uid"].ToString());
}
}
so basically, if the uid parameter is ANYTHING other than null, (a number, random string, other garbage) you are going to try and turn it into a guid. and that's obviously causing failures... put some logging in, and record the values of UID that are being submitted.
You should probably be using something like tryParse, instead of just puking an exception.
if(string.IsNullOrEmpty(s))
Console.WriteLine("Null or Empty");
Guid g;
Guid.TryParse(s, out g);
if(g == Guid.MinValue)
Console.WriteLine("Couldn't Parse");
else
Console.WriteLine("G: {0}", g);

Answer 2

Guid should contain 32 digits with 4 dashes (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)
Does tihs 0fcc9582-386c-4738-943d-36e09c8df4b meet to requirement? You lost one digit in last part. You have 11 digit instead of 12.

Answer 3

Based on the current answers and comments and the fact that you use Umbraco I supect the QueryString is delivered to you in an encoded form. Better make sure that what we get is sane and valid and in the format we can actually handle it. The main improvement is in usimg HttpUtility.Decode to get the querystring into shape.
private Guid? PetitionGuid
{
get
{
Guid? guid = null;
var raw = Page.Request.QueryString["uid"];
if (!String.IsNullOrEmpty(raw))
{
var decoded = HttpUtility.UrlDecode(raw);
Guid parsed;
if (Guid.TryParse(decoded, out parsed))
{
guid = parsed;
}
else
{
Trace.WriteLine(String.Format(
"illigal uid {0}:{1}", raw,decoded));
}
}
return guid;
}
}