I really hate sometimes how IDictionary<TKey, TValue> [key] will throw an exception if the key doesn't exist in the dictionary.
Of course there is TryGetValue(), but that seems to have been optimized for performance and not usability.
So I thought, oh I'll just make an extension method for it - which I did :
public static class CollectionExtensions { public static TType GetValueOrDefault<TKeyType, TValue, TType>(this IDictionary<TKeyType, TType> dictionary, TKeyType key) { TType value = default(TType); // attempt to get the value of the key from the dictionary // if the key doesn't exist just return null if (dictionary.TryGetValue(key, out value)) { return value; } else { return default(TType); } } } This works fine EXCEPT I cannot seem to get type inference working.
Obviously I want to be able to do the following :
var extraDataLookup = new Dictionary<string, string>(); extraDataLookup["zipcode"] = model.Zipcode; and then be able to access the value :
var zipcode = extraDataLookup.GetValueOrDefault("zipcode"); var foo = extraDataLookup.GetValueOrDefault("foo"); // should be null I've looked at a few things about type inference, inlucing Jon Skeet's article and even sourcecode to System.Linq.Enumerable in reflector but seem to be missing something.
This works :
extraDataLookup.GetValueOrDefault<string, string,string> ("foo") but this doesn't
extraDataLookup.GetValueOrDefault ("foo") What should I be doing.
PS. I'm only looking for solutions to the generic type inference problem, not any other suggestions. Thanks.
