C＃| SortedDictionary.Add()方法

这用于将指定的键和值添加到已排序的字典中。元素根据TKey排序。

句法：

public void Add (TKey key, TValue value);

参数：

key: It is the key of the element to add.
value: It is the value of the element to add. The value can be null for reference types.

例外情况：

• ArgumentNullException：如果键为null。
• ArgumentException：如果字典中已经存在具有相同键的元素。

下面是说明使用Dictionary .Add()方法的程序：

范例1：

// C# code to add the specified key
// and value into the SortedDictionary
using System;
using System.Collections.Generic;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Create a new SortedDictionary
        // of strings, with string keys.
        SortedDictionary myDict = 
           new SortedDictionary();
  
        // 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);
  
        // Displaying the key/value
        // pairs in myDict
        Console.WriteLine("The key/value pairs"
                          + " in myDict are : ");
  
        foreach(KeyValuePair kvp in myDict)
        {
            Console.WriteLine("Key = {0}, Value = {1}",
                              kvp.Key, kvp.Value);
        }
    }
}

输出：

Total key/value pairs in myDict are : 6
The key/value pairs in myDict are : 
Key = Australia, Value = Canberra
Key = Belgium, Value = Brussels
Key = China, Value = Beijing
Key = India, Value = New Delhi
Key = Netherlands, Value = Amsterdam
Key = Russia, Value = Moscow

范例2：

// C# code to add the specified key
// and value into the SortedDictionary
using System;
using System.Collections.Generic;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Create a new SortedDictionary
        // of strings, with string keys.
        SortedDictionary myDict =
           new SortedDictionary();
  
        // 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");
  
        // The Add method throws an
        // exception if the new key is
        // already in the dictionary.
        try {
  
            myDict.Add("Russia", "Moscow");
        }
  
        catch (ArgumentException) {
  
            Console.WriteLine("An element with Key "
                  + "= \"Russia\" already exists.");
        }
    }
}

输出：

An element with Key = "Russia" already exists.

笔记：

• 键不能为null，但值可以为null。如果值类型TValue是引用类型。
• 此方法是O(log n)操作，其中n是SortedDictionary中的元素计数。

参考：

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