Dictionary TryGetValue NullReferenceException
.net, c#, dictionary, nullreferenceexception
Solution
I think the only way you could have that exception is if your dictionary is null.
_dicCache.TryGetValue(objID, out newObject);
`null` is not a valid argument for the key (if `TKey` is a reference type), though in your case it's `int` so cannot be null. You'd see an `ArgumentNullException` if passing a `null` value for `key` anyway.
Are you sure `_dicCache` is not `null`? I would check the value of the assignment:
_dicCache = (Dictionary<int, T>)HttpContext.Current.Cache.Get(Name);
Problem
I am getting NullReferenceException at the `_dicCache.TryGetValue(objID, out newObject);` line. And I have no Idea why this is happening at all. Can comeone point me to the right direction please? Here is my class: ``` public class Cache<T> { public string Name { get; set; } private Dictionary<int, T> _dicCache = new Dictionary<int, T>(); public void Insert(int objID, T obj) { try { _dicCache.Add(objID, obj); HttpContext.Current.Cache.Insert(Name, _dicCache, null, DateTime.Now.AddMinutes(10), TimeSpan.FromMinutes(0)); } catch (Exception) { throw; } } public bool Get(int objID, out T obj) { _dicCache = (Dictionary<int, T>)HttpContext.Current.Cache.Get(Name); try { return _dicCache.TryGetValue(objID, out obj); } catch (Exception) { throw; } } } ``` And here is how I call it: ``` Services.Cache<Entities.User> cache = new Services.Cache<Entities.User>(); cache.Name = Enum.Cache.Names.usercache.ToString(); Entities.User user = new Entities.User(); cache.Get(pUserId, out user); ``` I Also have tried to change to Get class to: ``` public T Get(int objID, out T obj) { _dicCache = (Dictionary<int, T>)HttpContext.Current.Cache.Get(Name); T newObject = (T)Activator.CreateInstance<T>(); try { _dicCache.TryGetValue(objID, out newObject); obj = newObject; return obj; } catch (Exception) { throw; } } ``` But I still get the same NullReferenceException at the `_dicCache.TryGetValue(objID, out newObject);` line.