csharp [TryAdd] KeyがなければValueと共に追加します。#ExtensionMethod

Posted 2021-05-12

public static bool TryAdd<TKey, TValue>(this IDictionary<TKey, TValue> dict, TKey key, TValue addValue)
{
  bool canAdd = !dict.ContainsKey(key);
  
  if (canAdd)
  {
    dict.Add(key, addValue);
  }
  
  return canAdd;
}

public static bool TryAdd<TKey, TValue>(this IDictionary<TKey, TValue> dict, TKey key, Func<TKey, TValue> addValueFactory)
{
  bool canAdd = !dict.ContainsKey(key);
  
  if (canAdd)
  {
    dict.Add(key, addValueFactory(key));
  }
  
  return canAdd;
}