学用 ASP.Net 之 System.Collections.SortedList 类

SortedList 是能自动排序的 "Key/Value" 列表类(排序是依据 Key), 并能通过索引访问元素.

它像是 Hashtable(哈希表)的升级, 它们的每个元素都是视为一个 DictionaryEntry(Key/Value) 结构体.

正因为它比 Hashtable 多出了排序和索引, 所以效率不及 Hashtable.

---

主要成员:

---

/* 属性 */

Capacity;        //容量

Count;           //元素数

Keys;            //键集合(ICollection)

Values;          //值集合(ICollection)



/* 方法 */

Add()           //添加

Clear()         //清空

Contains()      //是否包含指定键

ContainsKey()   //同 Contains()

ContainsValue() //是否包含指定值

GetByIndex()    //根据索引取 Value

GetKey()        //根据索引获取 Key

GetKeyList()    //取键列表(IList)

GetValueList()  //取值列表(IList)

IndexOfKey()    //获取指定键的索引

IndexOfValue()  //获取指定值的索引

Remove()        //根据键值删除

RemoveAt()      //根据索引删除

SetByIndex()    //根据索引设置值

TrimToSize()    //优化容量(Capacity = Count)

---

元素会被自动排序:

---

protected void Button1_Click(object sender, EventArgs e)

{

    SortedList sList = new SortedList();

    sList.Add("2k", "x"); //值可以重复, 键不可以重复

    sList.Add("1k", "xx");

    sList.Add("4k", "xxx");

    sList.Add("3k", "xxxx");



    string str = "";

    foreach (DictionaryEntry de in sList)

    {

        str += string.Format("{0} : {1}\n", de.Key, de.Value);

    }

    TextBox1.Text = str;

}

/********

1k : xx

2k : x

3k : xxxx

4k : xxx

*********/

---

取值:

---

protected void Button1_Click(object sender, EventArgs e)

{

    SortedList sList = new SortedList();

    sList.Add("k1", "AAA");

    sList.Add("k2", "BBB");

    sList.Add("k3", "CCC");

    sList.Add("k4", "DDD");



    string s1 = sList["k2"].ToString();         //BBB

    string s2 = sList.GetByIndex(1).ToString(); //BBB



    string s3 = sList.GetKey(1).ToString();     //k2



    TextBox1.Text = s1 + "\n" + s2 + "\n" + s3;

}

---

改值:

---

protected void Button1_Click(object sender, EventArgs e)

{

    SortedList sList = new SortedList();

    sList.Add("4", "AAA");

    sList.Add("3", "BBB");

    sList.Add("2", "CCC");

    sList.Add("1", "DDD");



    sList["4"] = "aaa";

    sList.SetByIndex(1, "ccc");



    string str = "";

    for (int i = 0; i < sList.Count; i++)

    {

        str += sList.GetByIndex(i).ToString() + " "; //DDD ccc BBB aaa 

    }

    TextBox1.Text = str;

}

---

删除元素与获取索引:

---

protected void Button1_Click(object sender, EventArgs e)

{

    SortedList sList = new SortedList();

    sList.Add("4", "AAA");

    sList.Add("3", "BBB");

    sList.Add("2", "CCC");

    sList.Add("1", "DDD");



    if (sList.Contains("2")) { sList.Remove("2"); }           // 将删除 2/CCC

    if (sList.Count > 0) { sList.RemoveAt(sList.Count - 1); } // 将删除 4/AAA

    

    //分别查找剩余元素的索引

    int n1 = sList.IndexOfKey("3");     // 1

    int n2 = sList.IndexOfKey("1");     // 0



    int n3 = sList.IndexOfValue("BBB"); // 1

    int n4 = sList.IndexOfValue("DDD"); // 0



    sList.Clear();

    int n5 = sList.IndexOfKey("3");     //-1 : 找不到则返回 -1

    int n6 = sList.IndexOfValue("BBB"); //-1



    TextBox1.Text = string.Concat(n1 + "\n" + n2 + "\n" + n3 + "\n" + n4 + "\n" + n5 + "\n" + n6);

}

---

Capacity、Count 与 TrimToSize():

---

protected void Button1_Click(object sender, EventArgs e)

{

    SortedList sList = new SortedList(100); //预留储存 100 个元素的空间



    int n1 = sList.Capacity; //100

    int n2 = sList.Count;    //0



    sList.Add(1, 111);

    sList.Add(2, 222);

    int n3 = sList.Capacity; //100

    int n4 = sList.Count;    //2



    sList.TrimToSize();

    int n5 = sList.Capacity; //2

    int n6 = sList.Count;    //2



    TextBox1.Text = string.Concat(n1 + "\n" + n2 + "\n" + n3 + "\n" + n4 + "\n" + n5 + "\n" + n6);

}

---

分别获取键集合、值集合、键列表、值列表:

---

protected void Button1_Click(object sender, EventArgs e)

{

    SortedList sList = new SortedList(5);

    sList.Add("E", 5.55);

    sList.Add("C", 3.33);

    sList.Add("D", 4.44);

    sList.Add("A", 1.11);

    sList.Add("B", 2.22);



    ICollection keys = sList.Keys;

    ICollection values = sList.Values;



    IList keyList = sList.GetKeyList();

    IList valueList = sList.GetValueList();



    string s1, s2, s3, s4;

    s1 = s2 = s3 = s4 = "";



    foreach (var k in keys) { s1 += k.ToString() + " "; }                              //A B C D E 

    foreach (var v in values) { s2 += v.ToString() + " "; }                            //1.11 2.22 3.33 4.44 5.55 

    for (int i = 0; i < keyList.Count; i++) { s3 += keyList[i].ToString() + " "; }     //A B C D E 

    for (int i = 0; i < valueList.Count; i++) { s4 += valueList[i].ToString() + " "; } //1.11 2.22 3.33 4.44 5.55 



    TextBox1.Text = s1 + "\n" + s2 + "\n" + s3 + "\n" + s4;

}

---