C＃|从哈希表中删除具有指定键的元素

Hashtable类表示键和值对的集合，这些键和值对是根据键的哈希码进行组织的。该键用于访问集合中的项目。 Hashtable.Remove(Object)方法用于从Hashtable中删除具有指定键的元素。

句法：

public virtual void Remove (object key);

范围：

key: It is the key of the element to remove of type System.Object.

例外情况：

• ArgumentNullException：如果键为null。
• NotSupportedException：如果Hashtable是只读的或具有固定的大小。

例子：

// C# code to remove the element
// with the specified key from Hashtable
using System;
using System.Collections;
  
class GFG {
  
    // Driver code
    public static void Main()
    {
  
        // Creating a Hashtable
        Hashtable myTable = new Hashtable();
  
        // Adding elements in Hashtable
        myTable.Add("2", "Even & Prime");
        myTable.Add("3", "Odd & Prime");
        myTable.Add("4", "Even & non-prime");
        myTable.Add("9", "Odd & non-prime");
  
        // Print the number of entries in Hashtable
        Console.WriteLine("Total number of entries in Hashtable : " 
                                                  + myTable.Count);
  
        // To remove the elements from Hashtable
        // which has key as "3"
        myTable.Remove("3");
  
        // Print the number of entries in Hashtable
        Console.WriteLine("Total number of entries in Hashtable : " 
                                                  + myTable.Count);
  
        // To remove the elements from Hashtable
        // which has key as "4"
        myTable.Remove("4");
  
        // Print the number of entries in Hashtable
        Console.WriteLine("Total number of entries in Hashtable : " 
                                                  + myTable.Count);
  
        // Adding elements in Hashtable
        myTable.Add("g", "geeks");
        myTable.Add("c", "c++");
        myTable.Add("d", "data structures");
  
        // Print the number of entries in Hashtable
        Console.WriteLine("Total number of entries in Hashtable : " 
                                                  + myTable.Count);
  
        // To remove the elements from Hashtable
        // which has key as "c"
        myTable.Remove("c");
  
        // Print the number of entries in Hashtable
        Console.WriteLine("Total number of entries in Hashtable : " 
                                                  + myTable.Count);
    }
}

输出：

Total number of entries in Hashtable : 4
Total number of entries in Hashtable : 3
Total number of entries in Hashtable : 2
Total number of entries in Hashtable : 5
Total number of entries in Hashtable : 4

参考：

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