Returning a default value. (C#)
-
21-08-2019 - |
Question
I'm creating my own dictionary and I am having trouble implementing the TryGetValue function. When the key isn't found, I don't have anything to assign to the out parameter, so I leave it as is. This results in the following error: "The out parameter 'value' must be assigned to before control leaves the current method"
So, basically, I need a way to get the default value (0, false or nullptr depending on type). My code is similar to the following:
class MyEmptyDictionary<K, V> : IDictionary<K, V>
{
bool IDictionary<K, V>.TryGetValue (K key, out V value)
{
return false;
}
....
}
Solution
You are looking for the default
keyword.
For example, in the example you gave, you want something like:
class MyEmptyDictionary<K, V> : IDictionary<K, V>
{
bool IDictionary<K, V>.TryGetValue (K key, out V value)
{
value = default(V);
return false;
}
....
}
OTHER TIPS
default(T)
return default(int);
return default(bool);
return default(MyObject);
so in your case you would write:
class MyEmptyDictionary<K, V> : IDictionary<K, V>
{
bool IDictionary<K, V>.TryGetValue (K key, out V value)
{
... get your value ...
if (notFound) {
value = default(V);
return false;
}
}
....
}
Licensed under: CC-BY-SA with attribution
Not affiliated with StackOverflow