Remove all elements from the Hashtable in C#

To remove all elements from the Hashtable, the code is as follows −

Example

 Live Demo

using System;
using System.Collections;
public class Demo {
   public static void Main() {
      Hashtable hash = new Hashtable(10);
      hash.Add("1", "A");
      hash.Add("2", "B");
      hash.Add("3", "C");
      hash.Add("4", "D");
      hash.Add("5","E");
      hash.Add("6", "F");
      hash.Add("7", "G");
      hash.Add("8","H");
      hash.Add("9", "I");
      hash.Add("10", "J");
      Console.WriteLine("Hashtable Key and Value pairs...");
      foreach(DictionaryEntry entry in hash) {
         Console.WriteLine("{0} and {1} ", entry.Key, entry.Value);
      }
      Console.WriteLine("Is the Hashtable having fixed size? = "+hash.IsFixedSize);
      Console.WriteLine("Count of entries in Hashtable = "+ hash.Count);
      hash.Clear();
      Console.WriteLine("Count of entries in Hashtable (updated) = "+hash.Count);
   }
}

Output

This will produce the following output −

Hashtable Key and Value pairs...
10 and J
1 and A
2 and B
3 and C
4 and D
5 and E
6 and F
7 and G
8 and H
9 and I
Is the Hashtable having fixed size? = False
Count of entries in Hashtable = 10
Count of entries in Hashtable (updated) = 0

Example

Let us see another example −

 Live Demo

using System;
using System.Collections;
public class Demo {
   public static void Main() {
      Hashtable hash = new Hashtable(10);
      hash.Add("One", "100");
      hash.Add("Two", "200");
      hash.Add("Three", "300");
      hash.Add("Four", "400");
      hash.Add("Five","500");
      Console.WriteLine("Hashtable Key and Value pairs...");
      foreach(DictionaryEntry entry in hash) {
         Console.WriteLine("{0} and {1} ", entry.Key, entry.Value);
      }
      Console.WriteLine("Count of entries in Hashtable = "+ hash.Count);
      hash.Clear();
      Console.WriteLine("Count of entries in Hashtable (updated) = "+hash.Count);
   }
}

Output

This will produce the following output −

Hashtable Key and Value pairs...
One and 100
Five and 500
Three and 300
Two and 200
Four and 400
Count of entries in Hashtable = 5
Count of entries in Hashtable (updated) = 0