Delete a node from the end of doubly linked list in c#

Csharp program for Delete a node from the end of doubly linked list. Here problem description and explanation.

// Include namespace system
using System;
// Csharp program for
// Delete a node from the end of doubly linked list
public class LinkNode
{
	public int data;
	public LinkNode next;
	public LinkNode prev;
	public LinkNode(int data)
	{
		this.data = data;
		this.next = null;
		this.prev = null;
	}
}
public class DoublyLinkedList
{
	public LinkNode head;
	public LinkNode tail;
	public DoublyLinkedList()
	{
		// Set inital value
		this.head = null;
		this.tail = null;
	}
	// Insert new node at end position
	public void insert(int value)
	{
		// Create a node
		var node = new LinkNode(value);
		if (this.head == null)
		{
			// Add first node
			this.head = node;
			this.tail = node;
			return;
		}
		// Add node at last position
		this.tail.next = node;
		node.prev = this.tail;
		this.tail = node;
	}
	// Display node element of doubly linked list
	public void display()
	{
		if (this.head == null)
		{
			Console.WriteLine("Empty Linked List");
		}
		else
		{
			Console.WriteLine("\nLinked List Head to Tail :");
			// Get first node of linked list
			var temp = this.head;
			// iterate linked list 
			while (temp != null)
			{
				// Display node value
				Console.Write("  " + temp.data);
				// Visit to next node
				temp = temp.next;
			}
		}
	}
	// Remove the given node from end of linked list
	public void deletionFromEnd(int key)
	{
		if (this.head == null)
		{
			// Empty linked list
			return;
		}
		LinkNode auxiliary = null;
		var temp = this.tail;
		// Find the deleted node
		while (temp != null && auxiliary == null)
		{
			if (temp.data == key)
			{
				// We found deleted node
				auxiliary = temp;
			}
			// Visit to previous node
			temp = temp.prev;
		}
		if (auxiliary != null)
		{
			// When we get deleted node
			if (auxiliary.prev != null)
			{
				// When previous node present
				auxiliary.prev.next = auxiliary.next;
			}
			if (auxiliary.next != null)
			{
				// When next node present
				auxiliary.next.prev = auxiliary.prev;
			}
			if (this.head == auxiliary)
			{
				// When delete head node
				this.head = this.head.next;
			}
			if (auxiliary == this.tail)
			{
				// When delete last node
				this.tail = this.tail.prev;
			}
			auxiliary = null;
		}
		else
		{
			Console.WriteLine("\nNode not exist " + key);
		}
	}
	public static void Main(String[] args)
	{
		var dll = new DoublyLinkedList();
		// Insert following linked list nodes
		dll.insert(1);
		dll.insert(2);
		dll.insert(9);
		dll.insert(4);
		dll.insert(5);
		dll.insert(2);
		dll.insert(7);
		dll.insert(9);
		Console.Write("\nBefore Delete");
		dll.display();
		var key = 2;
		dll.deletionFromEnd(key);
		Console.Write("\nAfter Delete Node " + key.ToString());
		dll.display();
	}
}

Output

Before Delete
Linked List Head to Tail :
  1  2  9  4  5  2  7  9
After Delete Node 2
Linked List Head to Tail :
  1  2  9  4  5  7  9