C＃|字典清除方法

此方法用于从Dictionary 中删除所有键/值对。

句法：

public void Clear ();

下面是说明上述方法的用法的程序：

范例1：

// C# code to remove all pairs
// from Dictionary
using System;
using System.Collections.Generic;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Create a new dictionary of
        // strings, with string keys.
        Dictionary myDict = 
          new Dictionary();
  
        // Adding key/value pairs in myDict
        myDict.Add("Australia", "Canberra");
        myDict.Add("Belgium", "Brussels");
        myDict.Add("Netherlands", "Amsterdam");
        myDict.Add("China", "Beijing");
        myDict.Add("Russia", "Moscow");
        myDict.Add("India", "New Delhi");
  
        // To get count of key/value pairs in myDict
        Console.WriteLine("Total key/value pairs "+
                "in myDict are : " + myDict.Count);
  
        // Remove all pairs from the Dictionary
        myDict.Clear();
  
        Console.WriteLine("After clear operation");
  
        // To get count of key/value pairs in myDict
        Console.WriteLine("Total key/value pairs in"+
                   " myDict  are : " + myDict.Count);
    }
}

输出：

Total key/value pairs in myDict are : 6
After clear operation
Total key/value pairs in myDict  are : 0

范例2：

// C# code to remove all pairs
// from Dictionary
using System;
using System.Collections.Generic;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Create a new dictionary of 
        // strings, with string keys.
        Dictionary myDict =
           new Dictionary();
  
        // Adding key/value pairs in myDict
        myDict.Add(9, 8);
        myDict.Add(3, 4);
        myDict.Add(4, 7);
        myDict.Add(1, 7);
  
        // To get count of key/value pairs in myDict
        Console.WriteLine("Total key/value pairs "+
                "in myDict are : " + myDict.Count);
  
        // Remove all pairs from the Dictionary
        myDict.Clear();
  
        Console.WriteLine("After clear operation");
  
        // To get count of key/value pairs in myDict
        Console.WriteLine("Total key/value pairs"+
             " in myDict  are : " + myDict.Count);
    }
}

输出：

Total key/value pairs in myDict are : 4
After clear operation
Total key/value pairs in myDict  are : 0

参考：

• https://docs.microsoft.com/zh-cn/dotnet/api/system.collections.generic.dictionary-2.clear?view=netframework-4.7.2