學用 ASP.Net 之 System.Collections.Specialized.NameValueCollection 類

NameValueCollection 相當於 Key 和 Value 都是字串的且能通過索引訪問的雜湊表.
主要成員:

/* 屬性 */AllKeys; //返回包含所有鍵的 string[]Count;   //Keys;    //鍵集合/* 方法 */Add();       //Clear();     //CopyTo();    //Get();       //根據索引或鍵取值, 有多個值時會用逗號隔開GetKey();    //根據索引取鍵GetValues(); //根據索引或鍵取值, 返回 string[]HasKeys();   //是否包含非 null 鍵Remove();    //根據鍵移除Set();       //改值; 若鍵不存在則同 Add()

其 Key 可為 null, 且可對應多個 Value:

protected void Button1_Click(object sender, EventArgs e){    NameValueCollection nv = new NameValueCollection();    nv.Add("k1", "AAA");    nv.Add("k2", "BBB");    nv.Add("k3", "CCC");    nv.Add(null, "DDD");    nv.Add("k2", "b");    nv.Add("k2", "bb");    nv.Add("k2", "bbb");    string str1 = nv["k1"]; //AAA    string str2 = nv["k2"]; //BBB,b,bb,bbb : 多個值會用逗號分開    string str3 = nv[1];    //BBB,b,bb,bbb    string str4 = nv[null]; //DDD    TextBox1.Text = str1 + "\n" + str2 + "\n" + str3 + "\n" + str4;}   

練習:

protected void Button1_Click(object sender, EventArgs e){    NameValueCollection nv = new NameValueCollection();    nv.Add("k1", "AAA");    nv.Add("k2", "BBB");    nv.Add("k3", "CCC");    nv.Add("k2", "b");    nv.Add("k2", "bb");    nv.Add("k2", "bbb");    int n = nv.Count; //3 : k1、k2、k3    nv.Set("k1", "aaa");    string str1 = nv.Get(0);    //aaa    string str2 = nv.Get("k1"); //aaa    string str3 = nv.GetKey(0); //k1    string[] sArr1 = nv.GetValues(0);    string[] sArr2 = nv.GetValues("k2");    string str4 = string.Join("; ", sArr1); //aaa    string str5 = string.Join("; ", sArr2);    TextBox1.Text = string.Format("{0}\n{1}\n{2}\n{3}\n{4}\n{5}", n, str1, str2, str3, str4, str5);}protected void Button2_Click(object sender, EventArgs e){    NameValueCollection nv = new NameValueCollection();    nv.Add("k1", "AAA");    nv.Add("k2", "BBB");    nv.Add("k3", "CCC");    nv.Add("k2", "b");    nv.Add("k2", "bb");    nv.Add("k2", "bbb");    NameValueCollection.KeysCollection keys = nv.Keys;    string str1 = "";    foreach (string s in keys) { str1 += s + ", "; } //k1, k2, k3,     string str2 = string.Join("; ", nv.AllKeys);     //k1; k2; k3     TextBox1.Text = str1 + "\n" + str2;}