代码
public class DictionaryEx<TKey, TValue> : IDictionary<TKey, TValue>
{
/// <summary> 用户存储数据的字典
/// </summary>
private IDictionary<TKey, TValue> _items;
/// <summary> 默认值
/// </summary>
private TValue _defaultValue;
/// <summary> 用于获取值的委托
/// </summary>
private Converter<TKey, TValue> _getValue;
/// <summary> 1返回_defaultValue, 2执行_getValue, 0抛出异常
/// </summary>
private int _mode = 0;#region 构造函数
/// <summary> 初始化 DictionaryEx , key不存在时返回defaultValue
/// </summary>
/// <param name="defaultValue">默认值</param>
public DictionaryEx(TValue defaultValue)
{
_items = new Dictionary<TKey, TValue>();
_defaultValue = defaultValue;
_mode = 1;
}/// <summary> 初始化 DictionaryEx , key不存在时返回defaultValue
/// </summary>
/// <param name="defaultValue">默认值</param>
/// <param name="comparer">比较键时要使用对象,如果为null则使用默认比较方法</param>
public DictionaryEx(TValue defaultValue, IEqualityComparer<TKey> comparer)
{
_items = new Dictionary<TKey, TValue>(comparer);
_defaultValue = defaultValue;
_mode = 1;
}/// <summary> 初始化 DictionaryEx 只读集合, key不存在时返回defaultValue
/// </summary>
/// <param name="defaultValue">默认值</param>
/// <param name="dictionary">内部字典</param>
public DictionaryEx(TValue defaultValue, IDictionary<TKey, TValue> dictionary)
{
Assertor.AreNull(dictionary, "dictionary");
_items = dictionary;
IsReadOnly = true;
_defaultValue = defaultValue;
_mode = 1;
}/// <summary> 初始化 DictionaryEx, key不存在时返回defaultValue
/// </summary>
/// <param name="defaultValue">默认值</param>
/// <param name="dictionary">内部字典</param>
/// <param name="isReadOnly">是否只读</param>
public DictionaryEx(TValue defaultValue, IDictionary<TKey, TValue> dictionary, bool isReadOnly)
{
Assertor.AreNull(dictionary, "dictionary");
_items = dictionary;
IsReadOnly = isReadOnly;
_defaultValue = defaultValue;
_mode = 1;
}/// <summary> 初始化 DictionaryEx 设定getValue委托,key不存在时执行委托,并加入集合
/// </summary>
/// <param name="getValue">获取值的委托</param>
public DictionaryEx(Converter<TKey, TValue> getValue)
{
Assertor.AreNull(getValue, "getValue");
_items = new Dictionary<TKey, TValue>();
_getValue = getValue;
_mode = 2;
}/// <summary> 初始化 DictionaryEx 设定getValue委托,key不存在时执行委托,并加入集合
/// </summary>
/// <param name="getValue">获取值的委托</param>
/// <param name="comparer">比较键时要使用对象,如果为null则使用默认比较方法</param>
public DictionaryEx(Converter<TKey, TValue> getValue, IEqualityComparer<TKey> comparer)
{
Assertor.AreNull(getValue, "getValue");
_items = new Dictionary<TKey, TValue>(comparer);
_getValue = getValue;
_mode = 2;
}/// <summary> 初始化 DictionaryEx 设定getValue委托,key不存在时执行委托,并加入集合
/// </summary>
/// <param name="getValue">获取值的委托</param>
/// <param name="isReadOnly">集合是否限制外部修改</param>
public DictionaryEx(Converter<TKey, TValue> getValue, bool isReadOnly)
{
Assertor.AreNull(getValue, "getValue");
_items = new Dictionary<TKey, TValue>();
_getValue = getValue;
IsReadOnly = isReadOnly;
_mode = 2;
}/// <summary> 初始化 DictionaryEx 设定getValue委托,key不存在时执行委托,并加入集合
/// </summary>
/// <param name="getValue">获取值的委托</param>
/// <param name="comparer">比较键时要使用对象</param>
/// <param name="isReadOnly">集合是否限制外部修改</param>
public DictionaryEx(Converter<TKey, TValue> getValue, IEqualityComparer<TKey> comparer, bool isReadOnly)
{
Assertor.AreNull(getValue, "getValue");
_items = new Dictionary<TKey, TValue>(comparer);
_getValue = getValue;
IsReadOnly = isReadOnly;
_mode = 2;
}/// <summary> 初始化 DictionaryEx 设定getValue委托,key不存在时执行委托,并加入集合
/// </summary>
/// <param name="getValue">获取值的委托</param>
/// <param name="dictionary">内部字典</param>
public DictionaryEx(Converter<TKey, TValue> getValue, IDictionary<TKey, TValue> dictionary)
{
Assertor.AreNull(getValue, "getValue");
Assertor.AreNull(dictionary, "dictionary");
_items = dictionary;
_getValue = getValue;
IsReadOnly = true;
_mode = 2;
}/// <summary> 初始化 DictionaryEx 设定getValue委托,key不存在时执行委托,并加入集合
/// </summary>
/// <param name="getValue">获取值的委托</param>
/// <param name="dictionary">内部字典</param>
/// <param name="isReadOnly">是否只读</param>
public DictionaryEx(Converter<TKey, TValue> getValue, IDictionary<TKey, TValue> dictionary, bool isReadOnly)
{
_items = dictionary;
_getValue = getValue;
IsReadOnly = isReadOnly;
_mode = 2;
}/// <summary> 初始化 DictionaryEx 只读集合
/// </summary>
/// <param name="dictionary">内部字典</param>
public DictionaryEx(IDictionary<TKey, TValue> dictionary)
{
Assertor.AreNull(dictionary, "dictionary");
IsReadOnly = true;
_items = dictionary;
_mode = 0;
}
#endregionprivate TValue ReturnValue(TKey key)
{
switch (_mode)
{
case 1:
return _defaultValue;
case 2:
var value = _getValue(key);
lock (this)
{
_items[key] = value;
}
return value;
default:
throw new KeyNotFoundException();
}
}public void Add(TKey key, TValue value)
{
this[key] = value;
}public bool ContainsKey(TKey key)
{
return _items.ContainsKey(key);
}public ICollection<TKey> Keys
{
get { return _items.Keys; }
}public bool Remove(TKey key)
{
Assertor.AreTrue(IsReadOnly, "集合为只读");
return _items.Remove(key);
}public bool TryGetValue(TKey key, out TValue value)
{
return TryGetValue(key, out value);
}public ICollection<TValue> Values
{
get { return _items.Values; }
}public TValue this[TKey key]
{
get
{
TValue value;
if (_items.TryGetValue(key, out value))
{
return value;
}
return ReturnValue(key);
}
set
{
Assertor.AreTrue(IsReadOnly, "集合为只读");
_items[key] = value;
}
}public void Add(KeyValuePair<TKey, TValue> item)
{
this[item.Key] = item.Value;
}public void Clear()
{
Assertor.AreTrue(IsReadOnly, "集合为只读");
_items.Clear();
}public bool Contains(KeyValuePair<TKey, TValue> item)
{
return _items.Contains(item);
}public void CopyTo(KeyValuePair<TKey, TValue>[] array, int arrayIndex)
{
((IDictionary<TKey, TValue>)_items).CopyTo(array, arrayIndex);
}public int Count
{
get { return _items.Count; }
}public bool IsReadOnly { get; private set; }
public bool Remove(KeyValuePair<TKey, TValue> item)
{
return Remove(item.Key);
}public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
{
return _items.GetEnumerator();
}System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
return _items.GetEnumerator();
}
}
调用
static void Main(string[] args)
{
//key不存在返回默认值 ,key不区分大小写 (构造函数重载可以设定内部集合,是否只读)
var dict = new DictionaryEx<string, string>("default", StringComparer.OrdinalIgnoreCase);
dict.Add("AAA", "aaa");
Console.WriteLine(dict["aAa"]); //aaa
Console.WriteLine(dict["Bbb"]); //default//key不存在,执行委托,返回value,并加入集合 , 集合本身为只读 (构造函数重载可以设定内部集合,key比较方式)
dict = new DictionaryEx<string, string>(key => "[" + key + "]", true);
Console.WriteLine(dict["Bbb"]); //[Bbb]
try
{
dict["Bbb"] = "newvalue"; //throw new NotSupportedException("集合为只读");
}
catch (Exception) { }//创建只读键值对集合
var innerDict = new Dictionary<string, string>();
dict = new DictionaryEx<string, string>(innerDict);
innerDict.Add("aaa", "aaa");
Console.WriteLine(dict["aaa"]);
try
{
dict["Bbb"] = "newvalue"; //throw new NotSupportedException("集合为只读");
}
catch (Exception) { }
try
{
Console.WriteLine(dict["bbb"]); //throw new KeyNotFoundException();
}
catch (Exception) { }}
Code CSDN
https://code.csdn.net/snippets/389634