ภาพรวม
HybridDictionary (ใน System.Collections.Specialized) ใช้ ListDictionary ตอนเล็ก และสลับเป็น Hashtable ตอนใหญ่อัตโนมัติ คุณสมบัติ SyncRoot ใช้สำหรับล็อกการเข้าถึงแบบ thread-safe
ตัวอย่างที่ 1: ตรวจสอบคุณสมบัติและล็อก SyncRoot
using System;
using System.Collections;
using System.Collections.Specialized;
public class Demo
{
public static void Main()
{
HybridDictionary dict1 = new HybridDictionary();
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("HybridDictionary1 elements...");
foreach (DictionaryEntry d in dict1)
{
Console.WriteLine(d.Key + " " + d.Value);
}
Console.WriteLine("Is the HybridDictionary1 having fixed size? = " + dict1.IsFixedSize);
Console.WriteLine("If HybridDictionary1 read-only? = " + dict1.IsReadOnly);
Console.WriteLine("Is HybridDictionary1 synchronized = " + dict1.IsSynchronized);
HybridDictionary dict2 = new HybridDictionary();
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("\nHybridDictionary2 elements...");
foreach (DictionaryEntry d in dict2)
{
Console.WriteLine(d.Key + " " + d.Value);
}
Console.WriteLine("Is HybridDictionary1 equal to HybridDictionary2? = " + (dict1.Equals(dict2)));
Console.WriteLine("\nSynchronize access...");
lock (dict2.SyncRoot)
{
foreach (DictionaryEntry d in dict2)
{
Console.WriteLine(d.Key + " " + d.Value);
}
}
}
}
ผลลัพธ์
HybridDictionary1 elements... A Books B Electronics C Smart Wearables D Pet Supplies E Clothing F Footwear Is the HybridDictionary1 having fixed size? = False If HybridDictionary1 read-only? = False Is HybridDictionary1 synchronized = False HybridDictionary2 elements... 1 One 2 Two 3 Three 4 Four 5 Five 6 Six Is HybridDictionary1 equal to HybridDictionary2? = False Synchronize access... 1 One 2 Two 3 Three 4 Four 5 Five 6 Six
ตัวอย่างที่ 2: HybridDictionary ขนาดเล็กพร้อมล็อก
using System;
using System.Collections;
using System.Collections.Specialized;
public class Demo
{
public static void Main()
{
HybridDictionary dict = new HybridDictionary();
dict.Add("A", "SUV");
dict.Add("B", "MUV");
dict.Add("C", "AUV");
Console.WriteLine("HybridDictionary elements...");
foreach (DictionaryEntry d in dict)
{
Console.WriteLine(d.Key + " " + d.Value);
}
Console.WriteLine("\nSynchronize access...");
lock (dict.SyncRoot)
{
foreach (DictionaryEntry d in dict)
{
Console.WriteLine(d.Key + " " + d.Value);
}
}
}
}
ผลลัพธ์
HybridDictionary elements... A SUV B MUV C AUV Synchronize access... A SUV B MUV C AUV
สรุป
- HybridDictionary สลับระหว่าง ListDictionary และ Hashtable อัตโนมัติ
- ใช้
lock(dict.SyncRoot)ครอบการอ่าน/เขียนเพื่อ thread-safety - ใน .NET ใหม่ ควรใช้
ConcurrentDictionary<TKey, TValue>แทน
