/// <summary>
/// return old value and set to new value.
/// </summary>
/// <typeparam name="TKey"></typeparam>
/// <typeparam name="TValue"></typeparam>
/// <param name="dict"></param>
/// <param name="key"></param>
/// <param name="newValue"></param>
/// <param name="defaultReturnValue"></param>
/// <returns></returns>
public static TValue GetAndSetValue <TKey, TValue>(this IDictionary <TKey, TValue> dict, TKey key,
TValue newValue, TValue defaultReturnValue = default(TValue))
{
if (dict == null)
{
throw new ArgumentNullException(nameof(dict));
}
try
{
return(dict.GetValueOrDefault(key, defaultReturnValue));
}
finally
{
dict[key] = newValue;
}
}
public static TValue GetValueOrDefault <TKey, TValue>(this IDictionary <TKey, TValue> dictionary, TKey key)
{
return(dictionary.GetValueOrDefault(key, default(TValue)));
}
