nullreferenceexception

Image a Person and a Group class with a many-to-many relationship. A person has a list of groups and a group has a list of people. When mapping Person to PersonDTO I have a stack overflow exception because AutoMapper can't handle the Person > Groups > Members > Groups > Members >... So here's the example code: public class Person { public string Name { get; set; } public List<Group> Groups { get; set; } } public class Group { public string Name { get; set; } public List<Person> Members { get; set; } } public class PersonDTO { public string Name { get; set; } public List<GroupDTO> Groups { get;

For a couple of days I am working on a WebBrowser based webscraper. After a couple of prototypes working with Threads and DocumentCompleted events, I decided to try and see if I could make a simple, easy to understand Webscraper. The goal is to create a Webscraper that doesn't involve actual Thread objects. I want it to work in sequential steps (i.e. go to url, perform action, go to other url etc. etc.). This is what I got so far: public static class Webscraper { private static WebBrowser _wb; public static string URL; //WebBrowser objects have to run in Single Thread Appartment for some

I'm working on a large project where, even with 10s of 1000s of automated tests and 100% code coverage, we're getting a ridiculous number of errors. About 95% of errors we get are NullReferenceExceptions. Is there any way to enforce null-checking at compile time? Barring that, is there any way to automagically enforce null-checking in unit tests without having to write the tests for null cases myself? You should look into Code Contracts . The static checker is only available for the higher-end VS editions, but that's basically what you're after. There are plenty of resources online, and <plug>

I am using the following code within a class: string filePath = HttpContext.Current.Server.MapPath("~/email/teste.html"); The file teste.html is in the folder But when it will open the file the following error is being generated: Object reference not set to an instance of an object. Don't use Server.MapPath. It's slow. Use this instead, HttpRuntime.AppDomainAppPath . As long as your web site is running, this property is always available to you. Then use it like this: string filePath = Path.Combine(HttpRuntime.AppDomainAppPath, "email/teste.html"); if the code is not running from within a

I have the following function: public static T TryGetArrayValue<T>(object[] array_, int index_) { ... //some checking goes up here not relevant to question dynamic boxed = array_[index_]; return (T)boxed; } When I call it in the following way, object a = new object(); object v = TUtils.TryGetArrayValue<object>(new object[] { a }, 0); (T)boxed throws a null reference exception. Any other type I put in there other than "object", it works perfectly fine. Any ideas what this is, and why it's throwing the exception? Edit: The reason why I use dynamic is to avoid exception when converting types, for

I have this code: using DC = MV6DataContext; using MV6; // Business Logic Layer // ... public DC.MV6DataContext dc = new DC.MV6DataContext(ConnectionString); IP ip = new IP(Request.UserHostAddress); dc.IPs.InsertOnSubmit(ip); dc.SubmitChanges(); // in Business Logic layer: public class IP : DC.IP { public IP(string address) { ... } } Upon attempting to InsertOnSubmit(ip), I get a NullReferenceException (Object reference not set to an instance of an object). dc is not null; ip and all properties of ip are not null; though some are empty. VS2008 won't let me step into InsertOnSubmit, so I have