Not able to use GetValueOrDefault() for Dictionary in C#

Question

I've defined a Dictionary with some custom type like this,

 public readonly Dictionary<PricingSection, View> _viewMappings = new Dictionary<PricingSection, View>();

Now when i try to do

_viewMappings.GetValueOrDefault(section);

section is of type PricingSection

i'm getting an error saying

Severity Code Description Project File Line Suppression State Error CS1061 'Dictionary' does not contain a definition for 'GetValueOrDefault' and no accessible extension method 'GetValueOrDefault' accepting a first argument of type 'Dictionary' could be found (are you missing a using directive or an assembly reference?)

Am i missing something ??

Answer 1

Am i missing something ??

You are missing the fact Dictionary does not contain any method of this name GetValueOrDefault

Dictionary<TKey,TValue> Class

Maybe you are looking for

Dictionary<TKey,TValue>.TryGetValue(TKey, TValue) Method

Gets the value associated with the specified key.

or

ImmutableDictionary.GetValueOrDefault<TKey, TValue> Method (IImmutableDictionary<TKey, TValue>, TKey)

Gets the value for a given key if a matching key exists in the dictionary.

---

You could however implement your own

public static class Extensions
{
    public static TValue GetValueOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dict,TKey key)
      =>  dict.TryGetValue(key, out var value) ? value : default(TValue);
}

---

If you are using any of the following, there are extension method overloads for IReadOnlyDictionary

• NET 5.0 RC1

• .NET Core 3.1 3.0 2.2 2.1 2.0

• .NET Standard 2.1

CollectionExtensions.GetValueOrDefault

Tries to get the value associated with the specified key in the dictionary