Question

Currently I’m using

var x = dict.ContainsKey(key) ? dict[key] : defaultValue 

I’d like some way to have dictionary[key] return null for nonexistant keys, so I could write something like

var x =  dict[key] ?? defaultValue; 

this also winds up being part of linq queries etc. so I’d prefer one-line solutions.

Answer 1

With an extension method:

public static class MyHelper {     public static V GetValueOrDefault<K, V>(this IDictionary<K, V> dic,                                              K key,                                              V defaultVal = default(V))     {         V ret;         bool found = dic.TryGetValue(key, out ret);         if (found) { return ret; }         return defaultVal;     }     void Example()     {         var dict = new Dictionary<int, string>();         dict.GetValueOrDefault(42, 'default');     } }