C＃|从HybridDictionary删除所有条目

HybridDictionary.Clear方法用于从HybridDictionary中删除所有条目。

句法：

public void Clear ();

下面给出了一些示例，以更好地理解实现：

范例1：

// C# code to removes all entries
// from the HybridDictionary.
using System;
using System.Collections;
using System.Collections.Specialized;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Creating a HybridDictionary named myDict
        HybridDictionary myDict = new HybridDictionary();
  
        // Adding key/value pairs in myDict
        myDict.Add("A", "Apple");
        myDict.Add("B", "Banana");
        myDict.Add("C", "Cat");
        myDict.Add("D", "Dog");
        myDict.Add("E", "Elephant");
        myDict.Add("F", "Fish");
  
        // Displaying the number of key/value
        // pairs in HybridDictionary myDict
        Console.WriteLine("Number of key/value pairs in myDict are : " 
                                                      + myDict.Count);
  
        // Displaying the key/value pairs in myDict
        Console.WriteLine("The key/value pairs in myDict are : ");
  
        foreach(DictionaryEntry de in myDict)
        {
            Console.WriteLine(de.Key + " --> " + de.Value);
        }
  
        // Removing all entries from myDict
        myDict.Clear();
  
        // Displaying the number of key/value
        // pairs in HybridDictionary myDict
        Console.WriteLine("Number of key/value pairs in myDict are : " 
                                                       + myDict.Count);
  
        // Displaying the key/value pairs in myDict
        Console.WriteLine("The key/value pairs in myDict are : ");
  
        foreach(DictionaryEntry de in myDict)
        {
            Console.WriteLine(de.Key + " --> " + de.Value);
        }
    }
}

输出：

Number of key/value pairs in myDict are : 6
The key/value pairs in myDict are : 
A --> Apple
B --> Banana
C --> Cat
D --> Dog
E --> Elephant
F --> Fish
Number of key/value pairs in myDict are : 0
The key/value pairs in myDict are : 

范例2：

// C# code to removes all entries
// from the HybridDictionary.
using System;
using System.Collections;
using System.Collections.Specialized;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Creating a HybridDictionary named myDict
        HybridDictionary myDict = new HybridDictionary();
  
        // Adding key/value pairs in myDict
        myDict.Add("I", "first");
        myDict.Add("II", "second");
        myDict.Add("III", "third");
        myDict.Add("IV", "fourth");
        myDict.Add("V", "fifth");
  
        // Displaying the number of key/value
        // pairs in HybridDictionary myDict
        Console.WriteLine("Number of key/value pairs in myDict are : " 
                                                      + myDict.Count);
  
        // Displaying the key/value pairs in myDict
        Console.WriteLine("The key/value pairs in myDict are : ");
  
        foreach(DictionaryEntry de in myDict)
        {
            Console.WriteLine(de.Key + " --> " + de.Value);
        }
  
        // Removing all entries from myDict
        myDict.Clear();
  
        // Displaying the number of key/value
        // pairs in HybridDictionary myDict
        Console.WriteLine("Number of key/value pairs in myDict are : " 
                                                       + myDict.Count);
  
        // Displaying the key/value pairs in myDict
        Console.WriteLine("The key/value pairs in myDict are : ");
  
        foreach(DictionaryEntry de in myDict)
        {
            Console.WriteLine(de.Key + " --> " + de.Value);
        }
    }
}

输出：

Number of key/value pairs in myDict are : 5
The key/value pairs in myDict are : 
I --> first
II --> second
III --> third
IV --> fourth
V --> fifth
Number of key/value pairs in myDict are : 0
The key/value pairs in myDict are :

笔记：

• Count设置为零，并且还会释放对集合元素中其他对象的引用。
• 如果该集合已经存储在Hashtable中，则该集合将保留在Hashtable中。
• 此方法是O(n)运算，其中n是Count。

参考：

• https://docs.microsoft.com/zh-cn/dotnet/api/system.collections.specialized.hybriddictionary.clear?view=netframework-4.7.2