public void ReadOnlyDictionaryAsReadOnlyDictionary()
{
// AsReadOnlyDictionary should not rewrap a ReadOnlyCollection
var dictionary = new Dictionary <int, int> {
[1] = 1, [2] = 4
};
IEnumerable <KeyValuePair <int, int> > readOnlyDictionary = new ReadOnlyDictionary <int, int>(dictionary);
Assert.AreSame(readOnlyDictionary, readOnlyDictionary.AsReadOnlyDictionary());
}
public void DictionaryAdapterAvoidsWrapping() {
var d = 5.Range().ToDictionary(i => i, i => i*i);
// existing readonly dictionary class is not wrapped
var rd = new ReadOnlyDictionary<int, int>(d);
rd.AsReadOnlyDictionary().AssertReferenceEquals(rd);
rd.AsIDictionary().AssertReferenceEquals(rd);
// back-and-forth of an IReadOnlyDictionary has no effect
var ar = d.AsReadOnlyDictionary();
ar.AsIDictionary().AssertReferenceEquals(ar);
ReadOnlyDic.AsIDictionary().AsReadOnlyDictionary().AssertReferenceEquals(ReadOnlyDic);
}
public void DictionaryAdapterAvoidsWrapping()
{
var d = 5.Range().ToDictionary(i => i, i => i * i);
// existing readonly dictionary class is not wrapped
var rd = new ReadOnlyDictionary <int, int>(d);
rd.AsReadOnlyDictionary().AssertReferenceEquals(rd);
rd.AsIDictionary().AssertReferenceEquals(rd);
// back-and-forth of an IReadOnlyDictionary has no effect
var ar = d.AsReadOnlyDictionary();
ar.AsIDictionary().AssertReferenceEquals(ar);
ReadOnlyDic.AsIDictionary().AsReadOnlyDictionary().AssertReferenceEquals(ReadOnlyDic);
}
/// <summary> /// Gets the value associated with a specified key as an option. /// </summary> /// <typeparam name="TKey">The type of the keys in <paramref name="source"/>.</typeparam> /// <typeparam name="TValue">The type of the values in <paramref name="source"/>.</typeparam> /// <param name="source">A source dictionary.</param> /// <param name="key">The key whose value to get.</param> /// <returns> /// An option containing the value associated with <paramref name="key"/> in <paramref /// name="source"/>, if it is found; otherwise, an empty option. /// </returns> /// <exception cref="ArgumentNullException"> /// <paramref name="source"/> or <paramref name="key"/> is <see langword="null"/>. /// </exception> public static Opt <TValue> GetValueOpt <TKey, TValue>(this ReadOnlyDictionary <TKey, TValue> source, TKey key) => source.AsReadOnlyDictionary().GetValueOpt(key);
