src/System.Private.CoreLib/src/System/Runtime/InteropServices/WindowsRuntime/DictionaryKeyCollection.cs

   1 // Licensed to the .NET Foundation under one or more agreements.
   2 // The .NET Foundation licenses this file to you under the MIT license.
   3 // See the LICENSE file in the project root for more information.
   4
   5 #nullable enable
   6 using System.Collections;
   7 using System.Collections.Generic;
   8 using System.Diagnostics;
   9
  10 namespace System.Runtime.InteropServices.WindowsRuntime
  11 {
  12     [DebuggerDisplay("Count = {Count}")]
  13     internal sealed class DictionaryKeyCollection<TKey, TValue> : ICollection<TKey>
  14     {
  15         private readonly IDictionary<TKey, TValue> dictionary;
  16
  17         public DictionaryKeyCollection(IDictionary<TKey, TValue> dictionary)
  18         {
  19             if (dictionary == null)
  20                 throw new ArgumentNullException(nameof(dictionary));
  21
  22             this.dictionary = dictionary;
  23         }
  24
  25         public void CopyTo(TKey[] array, int index)
  26         {
  27             if (array == null)
  28                 throw new ArgumentNullException(nameof(array));
  29             if (index < 0)
  30                 throw new ArgumentOutOfRangeException(nameof(index));
  31             if (array.Length <= index && this.Count > 0)
  32                 throw new ArgumentException(SR.Arg_IndexOutOfRangeException);
  33             if (array.Length - index < dictionary.Count)
  34                 throw new ArgumentException(SR.Argument_InsufficientSpaceToCopyCollection);
  35
  36             int i = index;
  37             foreach (KeyValuePair<TKey, TValue> mapping in dictionary)
  38             {
  39                 array[i++] = mapping.Key;
  40             }
  41         }
  42
  43         public int Count
  44         {
  45             get { return dictionary.Count; }
  46         }
  47
  48         bool ICollection<TKey>.IsReadOnly
  49         {
  50             get { return true; }
  51         }
  52
  53         void ICollection<TKey>.Add(TKey item)
  54         {
  55             throw new NotSupportedException(SR.NotSupported_KeyCollectionSet);
  56         }
  57
  58         void ICollection<TKey>.Clear()
  59         {
  60             throw new NotSupportedException(SR.NotSupported_KeyCollectionSet);
  61         }
  62
  63         public bool Contains(TKey item)
  64         {
  65             return dictionary.ContainsKey(item);
  66         }
  67
  68         bool ICollection<TKey>.Remove(TKey item)
  69         {
  70             throw new NotSupportedException(SR.NotSupported_KeyCollectionSet);
  71         }
  72
  73         IEnumerator IEnumerable.GetEnumerator()
  74         {
  75             return ((IEnumerable<TKey>)this).GetEnumerator();
  76         }
  77
  78         public IEnumerator<TKey> GetEnumerator()
  79         {
  80             return new DictionaryKeyEnumerator<TKey, TValue>(dictionary);
  81         }
  82     }  // public class DictionaryKeyCollection<TKey, TValue>
  83
  84
  85     internal sealed class DictionaryKeyEnumerator<TKey, TValue> : IEnumerator<TKey>
  86     {
  87         private readonly IDictionary<TKey, TValue> dictionary;
  88         private IEnumerator<KeyValuePair<TKey, TValue>> enumeration;
  89
  90         public DictionaryKeyEnumerator(IDictionary<TKey, TValue> dictionary)
  91         {
  92             if (dictionary == null)
  93                 throw new ArgumentNullException(nameof(dictionary));
  94
  95             this.dictionary = dictionary;
  96             enumeration = dictionary.GetEnumerator();
  97         }
  98
  99         void IDisposable.Dispose()
 100         {
 101             enumeration.Dispose();
 102         }
 103
 104         public bool MoveNext()
 105         {
 106             return enumeration.MoveNext();
 107         }
 108
 109         object? IEnumerator.Current
 110         {
 111             get { return ((IEnumerator<TKey>)this).Current; }
 112         }
 113
 114         public TKey Current
 115         {
 116             get { return enumeration.Current.Key; }
 117         }
 118
 119         public void Reset()
 120         {
 121             enumeration = dictionary.GetEnumerator();
 122         }
 123     }  // class DictionaryKeyEnumerator<TKey, TValue>
 124 }
 125
 126 // DictionaryKeyCollection.cs