A hash table is a collection that is used to store key-value pairs. So the hash table stores 2 values while storing just one value like the stack, array list and queue. These 2 values are an element of the hash table.

• To add an element to the queue, the Add method is used. The statement’s general syntax is given below.

ht.Add("key", "Value");

• ContainsKey method is used to determine whether the Hashtable contains a specific key.
• ContainsValue method is used to determine whether the Hashtable contains a specific value.

When you use foreach to enumerate hash table elements, the elements are retrieved as KeyValuePair objects.

            foreach (DictionaryEntry de in ht)
            {
                Console.WriteLine("Key = {0}, Value = {1}", de.Key, de.Value);
            }

Hastable Example:

            
            Hashtable ht = new Hashtable();
            
            // Add key-value pairs
            ht.Add("key1", "Value1");
            ht.Add("key2", "Value2");
            ht.Add("key3", "Value3");

            bool hasKey1 = ht.ContainsKey("key1");
            bool hasValue2 = ht.ContainsValue("Value1");

            // When you use foreach to enumerate hash table elements,
            // the elements are retrieved as KeyValuePair objects.
            foreach (DictionaryEntry de in ht)
            {
                Console.WriteLine("Key = {0}, Value = {1}", de.Key, de.Value);
            }

Program Output: