C＃| Dictionary.ContainsValue()方法

此方法用于检查Dictionary 是否包含特定值。

句法：

public bool ContainsValue (TValue value);

在这里，值是要在字典中找到的值。对于引用类型，该值可以为null。

返回值：如果Dictionary包含具有指定值的元素，则此方法返回true ，否则返回false 。

下面的程序说明了Dictionary .ContainsValue()方法的用法：

范例1：

// C# code to check if a value 
// is present or not in a 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");
  
        // Checking the value "India" but 
        // here "India" is the key
        if (myDict.ContainsValue("India"))
            Console.WriteLine("Value : India is present.");
  
        else
            Console.WriteLine("Value : India is not present.");
    }
}

输出：

Value : India is not present.

范例2：

// C# code to check if a value is
// present or not in a 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");
  
        // Checking for value Moscow
        if (myDict.ContainsValue("Moscow"))
            Console.WriteLine("Value : Moscow is present");
  
        else
            Console.WriteLine("Value : Moscow is absent");
    }
}

输出：

Value : Moscow is present

参考：

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