Pick.Net.Utilities 1.0.0-preview4

Pick.Net.Utilites

Various helper classes for C#.

Abstract collection classes

Abstract classes is designed to serve as a base class for creating read-only collections. Methods that modify the collection (i.e. Add, Clear, and Remove) will throw a NotSupportedException.

• AbstractReadOnlyCollection (ICollection, ICollection<T> & IReadOnlyCollection&lt<T>)
• AbstractReadOnlyList (IList, IList<T> & IReadOnlyList<T>)
• AbstractReadOnlyDictionary (IDictionary, IDictionary<TKey, TValue> & IReadOnlyDictionary<TKey, TValue>)

public class SingleItemCollection(string item) : AbstractReadOnlyCollection<string>
{
	public override int Count => 1;

	public override IEnumerator<string> GetEnumerator()
	{
		yield return item;
	}
}

var collection = new SimpleCollection("test");
var array = collection.ToArray();
// [ "test" ]
((ICollection<T>)collection).Add("another item")
// throws a NotSupportedException

Map

A dictionary-like collection with that allows covariance of the value type parameter and returns null instead of throwing a KeyNotFound exception when accessing a key not in the collection. Only supports reference type values.

var map = new Map<string, string>
{
	{ "key1", "value1" },
	{ "key2", "value2" },
	{ "key3", "value3" }
};

var value1 = map["key1"];
// "value1"
var value4 = map["key4"];
// null

IReadOnlyMap<string, object> objectMap = map;
var value2 = objectMap["key2"];
// "value2"

StringDictionary

A string-keyed dictionary that allows char spans to be used to get values

var map = new StringDictionary<object>
{
	{ "key1", "value1" },
	{ "key2", "value2" },
	{ "key3", "value3" }
};

ReadOnlySpan<char> keys = "key1;key2;key3";

var value1 = map[keys[..4]];
// "value1"
var value2 = map[keys[5..^5]];
// "value2"
var value3 = map[keys[^4..]];
// "value3"

DelegateHelper

Generic version of Delegate.CreateDelegate, Delegate.Combine and Delegate.Remove

// instead of
var handler = (Predicate<string>)Delegate.CreateDelegate(typeof(Predicate<string>), method);
// use
var handler = DelegateHelper.CreateDelegate<Predicate<string>>(method);

Shortcuts for System.Action and System.Func

Action<object> handler = DelegateHelper.CreateAction<object>(method);
Func<int, string, bool> handler = DelegateHelper.CreateFunc<int, string, bool>(method);

Get delegate parameter and return types

ImmutableArray<Type> types = DelegateHelper.GetParameterTypes<Action<string, int>>();
// [ typeof(string), typeof(int) ]
Type types = DelegateHelper.GetReturnType<Func<string>>();
// typeof(string)