8. 實現IDictionary<TKey, TValue>接口
由於前面實現了 IDictionary接口，現在實現IDictionary<TKey, TValue>也就沒什麼困難 的了，照葫蘆畫瓢。
首先改變類聲明：
public class ReversibleSortedList<TKey, TValue> :IDictionary<TKey, TValue>
IDictionary, IEnumerable<KeyValuePair<TKey, TValue>>, ICollection,
IEnumerable, ICollection<KeyValuePair<TKey, TValue>>
然後 實現ICollection<KeyValuePair<TKey, TValue>>接口成員：
bool ICollection<KeyValuePair<TKey, TValue>>.IsReadOnly
{
get
{
return false;
}
}
void ICollection<KeyValuePair<TKey, TValue>>.Add(
KeyValuePair<TKey, TValue> keyValuePair)
{
this.Add(keyValuePair.Key, keyValuePair.Value);
}
bool ICollection<KeyValuePair<TKey, TValue>>.Contains(
KeyValuePair<TKey, TValue> keyValuePair)
{
int num1 = this.IndexOfKey (keyValuePair.Key);
if ((num1 >= 0) && EqualityComparer<TValue>.Default.Equals(this.values[num1],
keyValuePair.Value))
{
return true;
}
return false;
}
void ICollection<KeyValuePair<TKey, TValue>>.CopyTo (
KeyValuePair<TKey, TValue>[] array, int arrayIndex)
{
if (array == null)
{
throw new ArgumentNullException ("array");
}
if ((arrayIndex < 0) || (arrayIndex > array.Length))
{
throw new ArgumentOutOfRangeException(
"arrayIndex", "Need a non-negative number");
}
if ((array.Length - arrayIndex) < this.Count)
{
throw new ArgumentException("ArrayPlusOffTooSmall");
}
for (int num1 = 0; num1 < this.Count; num1++)
{
KeyValuePair<TKey, TValue> pair1;
pair1 = new KeyValuePair<TKey, TValue>(
this.keys[num1], this.values[num1]);
array[arrayIndex + num1] = pair1;
}
}
bool ICollection<KeyValuePair<TKey, TValue>>.Remove(
KeyValuePair<TKey, TValue> keyValuePair)
{
int num1 = this.IndexOfKey(keyValuePair.Key);
if ((num1 >= 0) && EqualityComparer<TValue>.Default.Equals(
this.values[num1], keyValuePair.Value))
{
this.RemoveAt(num1);
return true;
}
return false;
}
需要注意，Count屬性和Clear 方法都是共用方法，不需要再次實現。
接下來實現 IDictionary<TKey, TValue>接口，它是最主要的接口，所有成員均為公 有的，前面我們已經實現了Add、ContainsKey方法，這裡不再列出：
ICollection<TKey> IDictionary<TKey, TValue>.Keys
{
get
{
return this.GetKeyListHelper();
}
}
ICollection<TValue> IDictionary<TKey, TValue>.Values
{
get
{
return this.GetValueListHelper();
}
}
public TValue this[TKey key] //Item屬性，就是索引器
{
get
{
TValue local1;
int num1 = this.IndexOfKey(key);
if (num1 >= 0)
{
return this.values [num1];
}
else
{
local1 = default(TValue);
return local1;
}
}
set
{
if (key == null)
{
throw new ArgumentNullException("key");
}
int num1 = Array.BinarySearch<TKey>(this.keys, 0, this._size, key,
this._sortDirectionComparer);
if (num1 >= 0)
{
this.values[num1] = value;
this.version++;
}
else
{
this.Insert (~num1, key, value);
}
}
}
public bool Remove(TKey key)
{
int num1 = this.IndexOfKey(key);
if (num1 >= 0)
{
this.RemoveAt(num1);
}
return (num1 >= 0);
}
public bool TryGetValue(TKey key, out TValue value)
{
int num1 = this.IndexOfKey (key);
if (num1 >= 0)
{
value = this.values[num1];
return true;
}
value = default(TValue);
return false;
}
另外需要添加一個RemoveAt方法：
// 移除指定索引元素
public void RemoveAt(int index)
{
if ((index < 0) || (index >= this._size))
{
throw new ArgumentOutOfRangeException ("index", "Index out of range");
}
this._size--;
if (index < this._size)
{
Array.Copy(this.keys, (int)(index + 1), this.keys, index,
(int)(this._size - index));
Array.Copy(this.values, (int)(index + 1), this.values, index,
(int)(this._size - index));
}
this.keys[this._size] = default (TKey);
this.values[this._size] = default(TValue);
this.version++;
}
最後，進行測試，這一次 不再使用int做為鍵，而改用string：
static void Main()
{
ReversibleSortedList<string, string> rs = new ReversibleSortedList<string, string>();
//添加元素
rs.Add("3", "a");
rs.Add("1", "b");
rs.Add ("2", "c");
rs.Add("6", "d");
rs.Add("5", "e");
rs.Add("4", "f");
//使用 DictionaryEntry打印鍵/值
foreach (KeyValuePair<string, string> d in rs)
{
Console.WriteLine (d.Key + " " + d.Value);
}
Console.WriteLine("刪除索引為“2”的“5”的元 素");
rs.Remove("2");
rs.Remove("5");
foreach (KeyValuePair<string, string> d in rs)
{
Console.WriteLine(d.Key + " " + d.Value);
}
}
ReversibleSortedList 0.7版本：實現 IDictionary<TKey, TValue>接口
運行結果：
1 b
2 c
3 a
4 f
5 e
6 d
刪除索引為“2”的“5”的元素
1 b
3 a
4 f
6 d
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