System.Console.WriteLine(u[0]);
System.Console.WriteLine(u[1]);
System.Console.WriteLine(u[2]);
2.3 话白
是不是很像Dictionary（词典类）的赋值取值方式了？但这只能用数字来索引；
3 字符串索引器
3.1 定义一个索引器类
public class MySimpleDictionary
private List<KeyValueEntity> keyValueEntitys = new List<KeyValueEntity>();
//索引器
public object this[string key]
foreach(KeyValueEntity keyValueEntity in keyValueEntitys)
if (keyValueEntity.key == key)
return keyValueEntity.value;
return null;
foreach (KeyValueEntity keyValueEntity in keyValueEntitys)
if (keyValueEntity.key == key)
keyValueEntity.value = value;
return;
KeyValueEntity newKeyValueEntity = new KeyValueEntity();
newKeyValueEntity.key = key;
newKeyValueEntity.value = value;
keyValueEntitys.Add(newKeyValueEntity);
public class KeyValueEntity
public string key { set; get; }
public object value { set; get; }
3.2 使用这个索引器类
MySimpleDictionary mydic = new MySimpleDictionary();
mydic["testKey0"] = "testValue0";
mydic["testKey1"] = "testValue1";
mydic["testKey2"] = "testValue2";
System.Console.WriteLine(mydic["testKey0"]);
System.Console.WriteLine(mydic["testKey1"]);
System.Console.WriteLine(mydic["testKey2"]);
3.3 话白
是不是更像Dictionary（词典类）的赋值取值方式了？但这只能用字符串来索引；
接下来，我们在此基础上改造一个泛型的；
4 泛型索引器
4.1 定义一个索引器类
public class MySimpleDictionary<T, U>
private List<KeyValueEntity<T, U>> keyValueEntitys = new List<KeyValueEntity<T, U>>();
//索引器
public U this[T key]
foreach (KeyValueEntity<T, U> keyValueEntity in keyValueEntitys)
if (keyValueEntity.key.Equals(key))
return keyValueEntity.value;
return default(U);
foreach (KeyValueEntity<T, U> keyValueEntity in keyValueEntitys)
if (keyValueEntity.key.Equals(key))
keyValueEntity.value = value;
return;
KeyValueEntity<T, U> newKeyValueEntity = new KeyValueEntity<T, U>();
newKeyValueEntity.key = key;
newKeyValueEntity.value = value;
keyValueEntitys.Add(newKeyValueEntity);
public class KeyValueEntity<T, U>
public T key { set; get; }
public U value { set; get; }
4.2 使用这个索引器类
MySimpleDictionary<string, string> dic = new MySimpleDictionary<string, string>();
dic["testKey0"] = "testValue0";
dic["testKey1"] = "testValue1";
dic["testKey2"] = "testValue2";
System.Console.WriteLine(dic["testKey0"]);
System.Console.WriteLine(dic["testKey1"]);
System.Console.WriteLine(dic["testKey2"]);
4.3 白话
到这里为止，我写的这个【简化版的Dictionary】跟【.net框架的Dictionary】相比还有一点较大的不同，如下：
1）数据结构算法不同
我写的词典类，是简单的键值对列表；
框架的词典类，是动态扩展的数组+hash冲突解决算法，有兴趣的同学去看源码，毕竟我这篇博客主要讲的是索引器；
5 组合索引器
5.1 定义一个索引器类
public class MySimpleDictionary
private List<GroupKeyValueEntity> keyValueEntitys = new List<GroupKeyValueEntity>();
//索引器
public object this[string group, string key]
foreach (GroupKeyValueEntity keyValueEntity in keyValueEntitys)
if (keyValueEntity.group == group && keyValueEntity.key == key)
return keyValueEntity.value;
return null;
foreach (GroupKeyValueEntity keyValueEntity in keyValueEntitys)
if (keyValueEntity.group == group && keyValueEntity.key == key)
keyValueEntity.value = value;
return;
GroupKeyValueEntity newKeyValueEntity = new GroupKeyValueEntity();
newKeyValueEntity.group = group;
newKeyValueEntity.key = key;
newKeyValueEntity.value = value;
keyValueEntitys.Add(newKeyValueEntity);
public class GroupKeyValueEntity
public string group { set; get; }
public string key { set; get; }
public object value { set; get; }
5.2 使用这个索引器类
MySimpleDictionary dic = new MySimpleDictionary();
dic["group0", "key0"] = "value0";
dic["group0", "key1"] = "value1";
dic["group0", "key2"] = "value2";
dic["group1", "key0"] = "value3";
dic["group1", "key1"] = "value4";
dic["group1", "key2"] = "value5";
System.Console.WriteLine(dic["group0", "key0"]);
System.Console.WriteLine(dic["group0", "key1"]);
System.Console.WriteLine(dic["group0", "key2"]);
System.Console.WriteLine(dic["group1", "key0"]);
System.Console.WriteLine(dic["group1", "key1"]);
System.Console.WriteLine(dic["group1", "key2"]);
5.3 白话
组合索引器不常用，对应的泛型就不在这里赘述了，有兴趣的同学不妨自己改造一下，毕竟泛型的用法还是很简单滴。。。
