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C# Dictionary.Keys用法及代码示例


此属性用于获取包含Dictionary中的键的集合。

用法:

public System.Collections.Generic.Dictionary<TKey, TValue>.KeyCollection Keys { get; }



返回值：它返回一个包含Dictionary中关键字的集合。

以下示例程序旨在说明上面讨论的属性的使用：

范例1：

// C# code to get the keys 
// in the 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<string, string> myDict =  
           new Dictionary<string, string>(); 
  
        // 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); 
  
        // To get the keys alone,  
        // use the Keys property. 
        Dictionary<string, string>.KeyCollection keyColl =  
                                              myDict.Keys; 
  
        // The elements of the KeyCollection 
        // are strongly typed with the type  
        // that was specified for dictionary  
        // keys 
        foreach(string s in keyColl) 
        { 
            Console.WriteLine("Key = {0}", s); 
        } 
    } 
}
输出： 
Total key/value pairs in myDict are:6
Key = Australia
Key = Belgium
Key = Netherlands
Key = China
Key = Russia
Key = India

范例2：

// C# code to get the keys in the 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<int, int> myDict =  
          new Dictionary<int, int>(); 
  
        // 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); 
  
        // To get the keys alone,  
        // use the Keys property. 
        Dictionary<int, int>.KeyCollection keyColl =  
                                       myDict.Keys; 
  
        // The elements of the KeyCollection 
        // are strongly typed with the type  
        // that was specified for dictionary keys. 
        foreach(int s in keyColl) 
        { 
            Console.WriteLine("Key = {0}", s); 
        } 
    } 
}
输出： 
Total key/value pairs in myDict are:4
Key = 9
Key = 3
Key = 4
Key = 1

参考：



相关用法


注：本文由纯净天空筛选整理自rupesh_rao大神的英文原创作品 C# | Dictionary.Keys Property。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。