ภาพรวม
ListDictionary (ใน System.Collections.Specialized) เป็นพจนานุกรมขนาดเล็กที่ใช้ linked list เนื้อหา เหมาะสำหรับข้อมูลน้อย (ประมาณ < 10 รายการ) เร็วกว่า Hashtable สำหรับขนาดเล็ก
ตัวอย่าง 1: สร้างและตรวจสอบคุณสมบัติ
using System;
using System.Collections;
using System.Collections.Specialized;
public class Demo {
public static void Main() {
ListDictionary dict = new ListDictionary();
dict.Add("1", "SUV");
dict.Add("2", "Sedan");
dict.Add("3", "Utility Vehicle");
dict.Add("4", "Compact Car");
dict.Add("5", "SUV");
dict.Add("6", "Sedan");
dict.Add("7", "Utility Vehicle");
dict.Add("8", "Compact Car");
dict.Add("9", "Crossover");
dict.Add("10", "Electric Car");
Console.WriteLine("ListDictionary elements...");
foreach (DictionaryEntry d in dict) {
Console.WriteLine(d.Key + " " + d.Value);
}
Console.WriteLine("\nIs the ListDictionary having fixed size? = " + dict.IsFixedSize);
Console.WriteLine("If ListDictionary read-only? = " + dict.IsReadOnly);
Console.WriteLine("Is ListDictionary synchronized = " + dict.IsSynchronized);
Console.WriteLine("The ListDictionary has the key K? = " + dict.Contains("K"));
Console.WriteLine("The ListDictionary has the key 9? = " + dict.Contains("9"));
}
}
ผลลัพธ์ตัวอย่าง 1
ListDictionary elements... 1 SUV 2 Sedan 3 Utility Vehicle 4 Compact Car 5 SUV 6 Sedan 7 Utility Vehicle 8 Compact Car 9 Crossover 10 Electric Car Is the ListDictionary having fixed size? = False If ListDictionary read-only? = False Is ListDictionary synchronized = False The ListDictionary has the key K? = False The ListDictionary has the key 9? = True
ตัวอย่าง 2: หลาย Dictionary และ Clear
using System;
using System.Collections;
using System.Collections.Specialized;
public class Demo {
public static void Main() {
ListDictionary dict1 = new ListDictionary();
dict1.Add("A", "Books");
dict1.Add("B", "Electronics");
dict1.Add("C", "Smart Wearables");
dict1.Add("D", "Pet Supplies");
dict1.Add("E", "Clothing");
dict1.Add("F", "Footwear");
Console.WriteLine("ListDictionary1 elements...");
foreach (DictionaryEntry d in dict1) {
Console.WriteLine(d.Key + " " + d.Value);
}
ListDictionary dict2 = new ListDictionary();
dict2.Add("1", "One");
dict2.Add("2", "Two");
dict2.Add("3", "Three");
dict2.Add("4", "Four");
dict2.Add("5", "Five");
dict2.Add("6", "Six");
Console.WriteLine("\nListDictionary2 elements...");
foreach (DictionaryEntry d in dict2) {
Console.WriteLine(d.Key + " " + d.Value);
}
Console.WriteLine("Count of key/value pairs in Dictionary 2 = " + dict2.Count);
ListDictionary dict3 = new ListDictionary();
dict3 = dict2;
Console.WriteLine("\nIs ListDictionary3 equal to ListDictionary2? = " + (dict3.Equals(dict2)));
dict3.Clear();
Console.WriteLine("Count of key/value pairs in Dictionary 3 = " + dict3.Count);
}
}
ผลลัพธ์ตัวอย่าง 2
ListDictionary1 elements... A Books B Electronics C Smart Wearables D Pet Supplies E Clothing F Footwear ListDictionary2 elements... 1 One 2 Two 3 Three 4 Four 5 Five 6 Six Count of key/value pairs in Dictionary 2 = 6 Is ListDictionary3 equal to ListDictionary2? = True Count of key/value pairs in Dictionary 3 = 0
สรุป
- เหมาะสำหรับข้อมูลน้อย (< 10 รายการ)
- คุณสมบัติ:
IsFixedSize,IsReadOnly,IsSynchronizedล้วนเป็นfalse Contains(key)ตรวจสอบคีย์Clear()ล้างข้อมูลทั้งหมด
