Suspect my brain isn't working today - I need to extract a list of keys, etc:
Dictionary<string, MyClass> myDict; List<String> myKeys = myDict.Keys; The second line fails to compile as the Keys property returns a "KeyCollection" class and not a list<> of key objects.
Using LINQ you can do the following...
List<String> myKeys = myDict.Keys.ToList(); However depending on what your goal is with the keys (selective enumeration etc) it might make more sense to work with the key collection and not convert to a list.
using System.Linq; I never get used to all these extension methods that suddenly show up...KeyCollection implements the IEnumerable interface.
You can use an extension method to convert it to a list.
List<String> myKeys = myDict.Keys.ToList(); Or use a different constructor:
List<String> myKeys = new List<String>(myDict.Keys); Yes, you can try - IEnumerable<String> myKeys = myDict.Keys;
Always a good idea to use IEnumerable (a more generic type).
If you need a true list:
List<string> myKeys = new List<string>(myDict.Keys); I've been created a simplified Dictionary:
using System; using System.Collections; using System.Collections.Generic; namespace CS_Library { public sealed class Dict : IEquatable<Dict>, IDict { private ArrayList keys, values; private int LocalCount; public int Count { get => LocalCount; } public Dict() { keys = new ArrayList(); values = new ArrayList(); } public Dict(ArrayList keys, ArrayList values) { this.keys = keys; this.values = values; } ~Dict() { } public object this[object key] { get => values[keys.IndexOf(key)]; } public int Add(object key, object value) // The more strange is the Visual Studio don't color the 'value' { if (keys.IndexOf(key) > -1 || values.IndexOf(value) > -1) { return -1; } LocalCount = keys.Add(key); return values.Add(value); } public void Override(object newKey, object newValue, object key) { if (keys.IndexOf(newKey) > -1 || values.IndexOf(newValue) > -1) { return; } keys[keys.IndexOf(key)] = newKey; values[keys.IndexOf(key)] = newValue; } public void Delete(object key) { if (keys.IndexOf(key) == -1) { return; } values.RemoveAt(keys.IndexOf(key)); keys.Remove(key); } public void DeleteAt(int index) { if (index < 0 || index > keys.Count) { return; } keys.RemoveAt(index); values.RemoveAt(index); } public void Erase() { values = null; keys = null; } public void Rebuild(ArrayList newKeys, ArrayList newValues) { if (keys != null && values != null) { throw new InvalidOperationException("Expected 'Erase()' method before this one. Or the 'Queue_Rebuild()' method instead this one."); } keys = newKeys; values = newValues; } public void Queue_Rebuild(ArrayList newKeys, ArrayList newValues) { Erase(); Rebuild(newKeys, newValues); } public override bool Equals(object obj) { return Equals(obj as Dict); } public bool Equals(Dict other) { return other != null && EqualityComparer<ArrayList>.Default.Equals(keys, other.keys) && EqualityComparer<ArrayList>.Default.Equals(values, other.values) && LocalCount == other.LocalCount; } public override int GetHashCode() { return HashCode.Combine(keys, values, LocalCount); } public override string ToString() { string r = "{ "; bool first = true; for (int i = 0; i < LocalCount; i++) { if (!first) { r += ", "; } else { first = false; } r += $"{keys[i]}:{values[i]}"; } return r + " }"; } public static bool operator ==(Dict left, Dict right) { return EqualityComparer<Dict>.Default.Equals(left, right); } public static bool operator !=(Dict left, Dict right) { return !(left == right); } public static Dict operator +(Dict left, Dict right) { Dict r = left; for (int i = 0; i < right.Count; i++) { r.Add(right.keys[i], right.values[i]); } return r; } } } It's not finished, so you can do any changes.
