2010-05-06
Empty User Names despite authenticating successfully
Had an issue today where System.Web.HttpContext.Current.User.Identity.Name was returning String.Empty even though I was prompted to authenticate against the server when hitting the web page. After a few Googles I realized it was because the web.config was set to <authentication mode="None"/>. Changing it to "Windows" fixed the problem. I've never understood what that web.config line did in the past, since Auth is done at the IIS level and ASP.NET shouldn't really care. I guess now I know...
2008-10-28
Before you take any cookies, don't forget to hand .Net the jar
When you are using the System.Web objects to make a HttpWebRequest in .NET to a page which sets a cookie via Set-Cookie header, and you can't access that cookie in the HttpWebResponse object's cookie collection. This will make you angry, and confused. You'll dump the page contents and the headers to make sure you're loading the right page an passing the Set-Cookie header correctly. Then you'll find this MSDN library post, and realize that if you don't give the Request a jar (CookieCollection) ahead of the firing GetResponse() .NET just throws your cookies on the floor.So whenever you want the cookies don't forget:req = HTTPWebRequest.Create(url);req.CookiesCollection = new CookiesCollection();req.GetResponse();
2008-10-21
Why Microsoft never fails to piss me off
How can my Visual Studio compile fail because a file is locked by Visual Studio?
MS owns the OS
MS owns the IDE
MS owns the language
MS owns the compiler
MS owns the runtime
Is using an all MS stack somehow an unsupported combination?
2008-09-23
Avoiding duplicate Event subsubscriptions
I've recently stumbled upon .Net Events, well re-stumbled since I obviously knew about them w.r.t. Web Forms, but they are a painful faded memory at this point, thanks to Monorail. I really like .Net Events for writing code that can be super decoupled from infrastructure concerns like logging, as well as for objects that might need to relay status or other "events" to their parent without having to pass maintain a reference to the parent.
The only real downside is if you subscribe multiple times to an event, += in C#, you get called multiple times when the Event fires. I'm sure there's some upside to this in some convoluted usage scenario, but I sure can't think of it. So I had written a bunch of helper methods to subscribe a given handler to a given event, but do it in a non-duplicate fashion. As far as I can tell there's no way to ask the event who's subscribed in any meaningful way, at least w.r.t. dupe avoidance, so I just remove the handler before adding it:
handler -= value;
handler += value;
This was fine, but it required calling subEvent(handler); rather than using the default += method of associating a handler with an Event. To get around this I found the this very handy post on stackoverflow. This allowed me to handle the call to the duplicate prevention method from add, thereby keeping the normal sytax for Event handlers.
The one gotcha here is you need the protected Event as well, because when you define the add, remove for your public Event you lose the ability to reference it like a normal Event. Some people have done more in-depth IL analysis of why, but for my purposes, I just use the protected Event when I want to throw it or otherwise use it so I don't get "The event "blah" can only appear on the left hand side of += or -=" errors
2008-09-22
NVelocity object properties gotcha
I always manage to forget that NVelocity won't show regular class variables in views, it has to be a property or method for you to be able to pull it from the view. Always waste a little time verifying the object is passed from the controller correctly, checking that the object isn't null in the view, etc. and then remember that I has to be a property or method. It's always the last thing you think of.
